COMMISSION F : WAVE PROPAGATION AND
REMOTE SENSING (Nov. '89 - Oct. '92)
Edited by Yoji Furuhama
F1. Wave Propagation
F1.1. Wave Propagation in the AtmosphereAn analysis using the geometrical optics theory was attempted to determine the propagation
characteristics in a nonuniform air in which the refractive index varies in both height and range
due to a small-scale nonuniform air mass occurring in the propagation path [Oka, 1990].
Propagation of electromagnetic waves in the stratified atmosphere with negative gradient of themodified refractive index was analyzed by using wave theory [Kawaguchi, 1992]. The
distribution of the modified refractive index for the middle layer in the atmosphere can beapproximated by an even power of the height.
Propagation test of air-ground path was carried out on 900MHz band. Atmospheric parameterssuch as effective radius factor k were studied for estimating air-ground long path propagation
characteristics [Akeyama et al., 1990a]. In order to predict the fading occurrence probability on
microwave line-of- sight links, the radio meteorological influences on fading occurrence werestudied [Sasaki et al., 1990].
Radiative transfer equation was solved for optical waves propagating in the turbulent
atmosphere coexistent with fog particles, by combining the small angle and the diffusion
approximations. Numerical results were given for the wavelength 0.6328mm and for several
turbulence strengths and sizes, to see the relative contributions of turbulence and fog particles tointensity [Zhang et al., 1990].

F1.2. Hydrometeors and Other Particles
A method was presented for obtaining the specific intensity of linearly polarized optical waves
propagated in discrete random media [Ito et al., 1989]. Solutions for the specific intensity wereobtained for large particles over a wide range of optical depths. A comparison with numericalsolutions was made to demonstrate the validity of the present theory. Incoherent wave
components generated by multiple scattering of waves in rain were calculated at several
wavelengths in the microwave to millimeter region for medium and high rainfall rates [Oguchi,
1991]. The results indicate that the incoherency effect may become a problem in radio
communications at frequencies higher than 300 GHz.
Simultaneous propagation experiment at 82 GHz and 350 THz was made on a 1.4 km range in asnowy district. Analysis of the one-year data shows that millimeter wave suffers much lessattenuation than optical wave in snow and fog conditions, while suffers larger attenuation inrainy conditions, indicating a usefulness of millimeter and optical wave diversity operation[Awaka et al., 1991].
Propagation characteristics through suspended water and ice particles which makes up haze,fog, or clouds were examined for microwave and millimeter wave frequencies using a newly
developed model for the complex permittivity for water and ice [Liebe, et al., 1991].
Experimental data for attenuation and phase delay for a fog event were found to be consistent
with this model calculation [Liebe et al., 1989].
Depolarization characteristics of Ka-band satellite-to-ground path were investigated using theCS-2 and CS-3 beacon signal radiowaves (19.45 GHz, RHCP, EL=49.5deg), as concerns bothrain and ice effects. The ice depolarization effects were found to largely depend on the rainheight in the stratus rainfall events [Maekawa et al., 1990a]. The characteristics ofdepolarization fluctuations were examined, and the ice effects were also correlated with crosspolarized phase in the low attenuation range due to both rain and ice effects [Maekawa et al.,1990b]. A possible improvement of XPD by phase shifters specific to the ice depolarizations
was shown to be approximately estimated by the amplitude of these ice effects [Maekawa et al.,1991a]. On the other hand, nature of rapid changes in depolarization due to thunderclouds waspresented, and large canting angles of ice crystals due to both electrostatic and aerodynamic
forces were inferred. Also, their impact on linear dual polarization systems was suggested[Maekawa et al., 1992a].
Rain depolarization characteristics were examined in relation to difference of rainfall types
primarily caused by raindrop size distributions. The cross-polar phase which is important toestimate a possible improvement of XPD by depolarization canceller was found to be largely
affected by the raindrop size distributions rather than rain intensity [Maekawa et al., 1992b; c].
The effect of integration time on various attenuation statistics was discussed by using
attenuation time-series data at 19.5GHz with a 1 second measuring interval [Fukuchi, 1992b]. It
was found that the difference in cumulative distributions due to integration time was not
significant. The integration time effect was significant in duration time statistics. This may be
due to the rapidly varying scintillation imposed on the slowly varying rain-induced attenuation.

F1.3. Radio Meteorology
Formulas evaluating one-minute rain rate statistics, required for prediction of rain attenuation,using one-year, one-hour or 10-minute precipitation were presented [Irie, 1989]. They were
derived from the measured meteorological data in 18 cities in Japan. Prediction accuracy wasassessed in terms of r.m.s. and mean relative errors.
By examining measured one-minute rainrate data reported so far and one-hour rainrate dataobtained by AMeDAS in Japan, a simple conversion method of one-hour rain rate data to oneminute rain rate distribution was developed, and its high accuracy was confirmed [Karasawa andMatsudo, 1990b]. Based on the method, a couple of maps of one-minute rain rate statistics suchas 0.01% rain rate using AMeDAS data in Japan were developed [Karasawa and Matsudo,
1991].

F1.4. Optical Wave Propagation
The following novel precise angle gauge was proposed [Takano and Yonehara, 1990]. Incoming
laser light was fed to the system through two separate condensing lenses. The phase difference
between two rays were compensated by a phase modulator to hold a constant interferencecondition. The angle of the incoming light was measured by the modulation voltage. Owing toadvantages for accuracy and configuration, the angle gauge is suitable for navigation using
angular information.
The basic research of ISL and a laser radar was conducted [Takano, 1990]. The link analysis of
ISL and a laser radar for two missions were given to show the possibility of actual use. Then, anovel precise angle gauge was described. The phase difference between two extracted rays fromincoming laser light was compensated by a phase modulation. Instruments using beams tended
to suffer from performance degradation due to diffraction phenomena. The method to suppress
Fresnel diffraction by spatial filters was studied, theoretically and experimentally.
(Y. Karasawa)

F2. Remote Sensing
F2.1. Atmosphere
Atmospheric water vapor contents measured by the Microwave Scanning Radiometer aboard
MOS-1 satellite were found to agree with the ones measured by radiosonde after correcting
constant bias errors. Several causes of the bias errors were examined and discussed [Ojima etal., 1990].
The MU (Middle and Upper atmosphere) radar of Kyoto University which is a high-power VHF
radar for tropospheric and stratospheric observations revealed a lot of new phenomena inhierarchical structures associated with medium-scale cyclones such as convection cells on theBaiu front primarily based on high resolution vertical wind data, which were never obtained byother instruments [Fukao et al., 1991b].
The Jicamarca VHF radar in Peru, which is one of the largest high-power radars in the world,
detected reliable atmospheric echoes in the so-called "gap region" from 30 to 60 km heights.
These echoes was, for the first time, discriminated from clutter echoes, using both co-polarized
and cross-polarized arrays to monitor the clutter component which may enter the antennasidelobes [Maekawa et al., 1991b; 1992d].
Radio Acoustic Sounding System (RASS) which combines acoustic and radar techniques is a
useful tool for observations of temperature profiles in the troposphere and lower stratosphere.
The echo power loss of RASS caused by the distortion of the acoustic wavefront due to thetemperature gradient was theoretically analyzed to make clear the limitation in the heightcoverage [Masuda et al., 1990]. The accuracy of temperature measurement with the RASS using
a monochromatic acoustic pulse was found to be strongly affected by the lapse rate of theatmospheric temperature and the ratio between acoustic and radar pulse lengths by using a
numerical model. The optimum ratio was determined by a compromise between the practicalrequirement of the temperature accuracy and the sensitivity in the echo detection [Adachi et al.,1991]. On the other hand, it was found by a numerical simulation that a RASS using a chirped
acoustic pulse can correctly measure a wide rage of Doppler shifts and that the accuracy of thetemperature measurement was almost independent of the lapse rate of the temperature [Masuda
et al., 1992a].
The use of a RASS with the MU radar for tropospheric profiling has an advantage of high time
resolution observations of both temperature and vertical wind velocity. Preliminary results offrequency spectra of temperature and vertical wind velocity fluctuations were reported, and heat

flux profiles were derived [Tsuda et al., 1991]. A 1.3 GHz pulse Doppler radar aiming at remotewind profiling of lower atmosphere was developed by Communication Research Laboratory(CRL). The initial observation results indicated its usefulness for wind profiling under both fineand rainy weather conditions [Masuda et al., 1992b; 1992c].
The NASA's deep space explorer Voyager-2 brought the first chance of the occultation by
Neptune in the summer of 1992. On this occasion, NASA/JPL and ISAS made the collaborating
experiment of the occultation using Usuda Deep Space Center of ISAS [Hayashi et al., 1990].
To detect quite slight fluctuations of the phase and amplitude of the radio wave carrier causedby occultation, a high G/T receiving system was realized combining a 64-m antenna and highperformance maser amplifiers. An antenna driving scheme to suppress the gain reduction due toelevation change was developed to keep the phase stable despite the antenna distortion [Takano
et al., 1992]. From the radio science data obtained at 2.3 GHz at Usuda, a temperature-pressure
profile of the Neptune's atmosphere was retrieved for the pressure levels between about 1 mbar
and 2 bars. The resultant profile was compared with the one retrieved from the 8.4 GHz dataobtained at Camberra, Australia [Mizuno et al., 1990]. The method of data analysis in which thesignal frequency and amplitude were extracted from the Voyager Neptune radio science data
was described along with the estimates of possible errors affecting the frequency estimates in[Mizuno et al., 1992].

F2.2. Hydrometeors and Other Particles
A method to estimate raindrop size distribution (DSD) from a spaceborne radar measurement
was proposed. This method employs a path-integrated attenuation derived from surface echo
and a radar reflectivity profile, and estimates a set of DSD parameters characterizing the
precipitation profile along the path. An analysis result of airborne radar data, which
demonstrates the validity of this method, was also presented in [Kozu et al., 1990; 1991a; b].
Numerical solutions of the vector two-frequency radiative transfer equation were obtained toinvestigate the effects of multiple scattering on pulse propagation in rain. The shape andmagnitude of transmitted and reflected pulses were calculated, and the effects of multiple
scattering on communication and polarimetric interpretation of radar returns from rain werediscussed [Oguchi and Ito., 1990]. A numerical simulation was made, using dual-wavelengthradar technique, to retrieve rain rates from radar echoes calculated with and without multiple
scattering effects included. The result showed that the retrieved rain rate based on multiple
scattering calculation is always smaller than that based on radar equation [Oguchi et al., 1992].
A method to estimate a range profile of raindrop size distribution (DSD) from dual-frequency
radar data was proposed in [Meneghini and Kozu, 1991]. This method uses a recursive
procedure beginning at the range gate near the surface progressing backwards toward the storm
top, and provides 2n+1 parameters of DSD (n: the number of range gates). A test result of thismethod using a dual-frequency airborne radar data was also presented.
Analyses of dual-frequency airborne radar data were described for testing and evaluating rain
retrieval algorithms from space. Those include comparisons of path-averaged rain rates derived
from several algorithms, surface cross sections under rain and no-rain conditions, effects of
mixed-phase precipitation on the retrieval accuracy, and a method to estimate the raindrop size
distribution. Approximate criteria on combining the different retrieval algorithms were also
discussed [Meneghini et al., 1990; 1992].
Statical properties of the differential reflectivity Zdr estimated by dual-polarization rain radar

were examined by considering the dependence of the correlation between simultaneously
measured horizontally and vertically polarized signals on the raindrop incidence angle and therainfall rate for square law and logarithmic estimators [Ohsaki, 1991]. The effect of polarization
switching time on the statistics properties of Zdr was also examined in [Ohsaki, 1992]
A dual polarization radar technique was applied to observe anomalous wintertime thundercloudsin Japan. The differential reflectivity factor of the C-band radar discriminated extremely flat,
small ice particles and round and/or rotating, comparatively large ice particles. These
corresponded to "ice crystals" and "graupel", respectively, both of which play an important rolein thunderstorm electrification [Fukao et al., 1991a; Maekawa et al., 1991c]. The lightning
locations were seen along the edge of the cloud center with the echo intensities of about 30
dBZ, where the graupel and ice crystal echoes distributed at short range, suggesting the riming
electrification and resulting charge separation between the two kinds of ice particles [Maekawa
et al., 1992e]. Calibration of a rain radar for satellite slant path of CS-2 or CS-3 was performed
with the aid of ground based rain gauge near the earth station of Osaka Electro-Communication
University, and the accuracy of rain measurements was slightly improved by correcting
characteristics of the receiving amplifier according to the rainfall rate ranges [Miyazaki et al.,1990].
The measurement of linear depolarization ratio (LDR) at X band was conducted from theairborne multi-parameter rain radar which flew over tropical storms in the western Pacific. Veryhigh value of LDR was obtained in the melting layer which suggested the existence of highly
aspherical or irregular shaped hydrometeor particles in this height [Kumagai et al., 1991]. The
statistical relation among LDR value in the melting layer, dBZ values both at X band and Ka
band, and the difference between the two was studied [Kumagai et al., 1992a]. Also, theradiometer data at X and Ka band taken simultaneously in the experiment were analyzed andcompared with the radar data [Kumagai et al., 1992b].
Rain rate estimation properties of multiparameter radar measurements combining radarreflectivity and microwave attenuations were studied through simulations using a disdrometerdata set [Kozu and Nakamura, 1991]. For the simulation, the concept of the multiparametermeasurements was generalized to combine the radar reflectivity profile with a low spatial
resolution path attenuation. The simulation result indicated that this type of measurements
improved the rain rate estimation accuracy by a factor of 2 to 4 compared with the conventional
single parameter measurement.
Rain rates estimated from brightness temperature measured with Microwave ScanningRadiometer (MSR) on board the Marine Observation Satellite 1 (MOS-1) were compared witha satellite-derived index of precipitation intensity (SI) derived from GMS satellite data. Good
correlation between MSR- and SI-derived rain rates validated the rain rate retrieval algorithm[Ohsaki and Fujita., 1992].
An influence of ocean surface roughness on microwave passive measurements of rain from anairborne platform was evaluated in [Fujita, 1991]. A two-scale rough surface model was
adopted to characterize the microwave scattering signature from a rough ocean surface. The
results of computation showed that the nadir-looking configuration minimized the influence of
ocean surface roughness on rain measurements. A comparison between the theoretical results
and the measurements was also shown.
Because of the short decorrelation time of surface return signals for spaceborne pulsecompression rain radar, it is important to evaluate the decorrelation effect on the compressed
waveform of pulse-compression radars. In [Kozu, 1990; 1991], this decorrelation effect for
linear FM pulses was quantitatively evaluated through numerical calculations. It was shown thatthe transmit pulse width should be shorter than half the time at which the auto-correlation

function of scattered signal decreased 0.1, in order to keep the decorrelation effect negligible.
Tropical Rainfall Measuring Mission (TRMM) is the first space mission, bearing the first rainradar in space, dedicated to the measurements of rainfall in the tropics where 60 percent of the
global rainfall is concentrated [Okamoto and Tanaka, 1990]. Launch operation, mission
operation and data processing as well as the system design and development status of the
TRMM were presented in [Kozu et al., 1992a]. Rain radar is a key sensor of the TRMM
program to obtain a reliable rainfall data set over the whole tropical area. The radar has theminimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal
resolution of 4 km and a swath width of 220 km. The conceptual radar design study was
conducted by CRL in cooperation with NASA/GSFC. As a result, the active array radar was
selected as a reliable candidate , and development of the key devices has been conducted[Okamoto et al., 1990; 1991a; Ihara et al., 1991a; Kozu et al., 1992b; Takamatsu et al., 1992].
Integration of these key devices to compose an 8-element Bread Board Model was made. The
basic electric antenna beam scanning function by the switching of the 5-bit digital phase shifter
was confirmed. The preliminary measurements of both the transmitting and receiving pattern of
the 8-element active array antenna were also made to show good electric performance [Okamoto
et al. 1992].
Two rain rate retrieval algorithms for TRMM rain radar were proposed in [Okamoto et al.
1991b]. One is the backscattering method and the other is the attenuation method. These two
methods are complementary in the sense that the backscattering and attenuation based
techniques perform best at low and high rain rates, respectively. In the attenuation method, thesurface reference technique becomes useful over the ocean.
The effects of sea-surface clutter on rain measurements with a satellite-borne rain radar were
quantitatively evaluated for the case of the TRMM rain radar [Manabe et al., 1989].
Attenuation and backscatter properties of bright-band particles were examined by a sphericalcomposite dielectric model and by a concentric spherical model. Computations were made at
13.8 GHz, which was to be used by the TRMM space-borne rain radar. It was found that the
scattering properties of bright-band strongly depended on models [Awaka, 1992].
A model of precipitation from stratus was examined using the slant-path attenuation and radar
data obtained during the ETS-II satellite experiment, and was used to simulate radar echoes
expected to be observed from satellite-borne rain radar such as the TRMM rain radar [Hatanaka
et al., 1992].
One-minute rain rate and raindrop size distribution measured by a tipping bucket raingage and adisdrometer at Darwin, Australia, were analyzed to characterize the tropical rainfall. It was
found that the raindrop size distribution and associated Z-R relation underwent an abrupt shift
between the convective and stratiform portions of tropical squall lines. This shift may haveimportant consequences for radar rainfall measurement [Short et al., 1990].

F2.3. Ocean and Sea Ice
Microwave backscatter from the sea surface were measured with a C-band Doppler radar atextremely low grazing angles. Dependence of the received power, the Doppler bandwidth, andthe Doppler shift on the wind speed and the wind direction was examined [Iguchi, 1989].
An HF ocean radar was developed by the Okinawa Radio Observatory of the Communications

Research Laboratory (ORO/CRL). The principles of HF ocean radar measurements of ocean
currents, surface wind, and wave height were described. Comparison between ocean parameters
deduced by the radar and those deduced by in-situ measurements showed a good agreement[Iguchi et al., 1990; Kuroiwa et al., 1992; Hisaki and Tokuda, 1992]. The difficulties inextracting sea-surface information using the existing scattering theory were pointed out in[Iguchi, 1991a]. The design and configuration of HF ocean radar developed at the ORO/CRL
were described in [Nozaki, 1991]. The effects of transmit/receive(T/R) switching waveforms on
the received signal in Frequency Modulated, Interrupted Continuous Wave (FMICW) radar
were examined. Simple square-wave switching was found to have advantages over random
code switching for a ground-wave HF ocean radar [Iguchi et al., 1989; Iguchi, 1991b]. Personal
computer programs for the automatic observation and the data processing of the HF ocean radar
were developed at the ORO/CRL [Umehara et al., 1991a]. Observations of the ocean currents
around Okinawa Main Island and Kume Island were made in 1989. Currents measured by theradar and those measured by a research vessel were compared. Diurnal and semi-diurnal tidal
currents were analyzed [Ohno, 1991a; Umehara et al., 1991b]. Kuroshio Current observations by
the HF ocean radar were carried out at Yakushima and Tanegashima Islands from October toDecember in 1990. Changes of the current velocities caused by a passing of the Kuroshio weredetected by the ocean radar [Ohno, 1991c; Ohno and Tokuda., 1992]. The first-order echoes ofthe HF ocean radar were examined statistically, and it was shown that splitting of first-orderechoes sometimes occurred due to the inhomogeneity of the current within the radar target cell
[Nadai, 1992]. Principles of measurements of the wave height and other wave parameters by the
HF ocean radar were described in [Iguchi, 1991c; Hisaki, 1992]. Comparison of the measured
wave parameters with those measured by ships and wave-buoys revealed some problems of themethod to estimate wave parameters by the radar. Sea-surface wind directions were deduced by
the Doppler spectra of the HF ocean radar echoes and a passage of a cold-front on the sea was
detected by the radar [Ohno, 1991b].
Ground based observation of sea ice by a UHF step-frequency radar was carried out on the sea
ice near Syowa Station, Antarctica. This was the first experiment to measure sea ice thickness
using a step-frequency radar system. The echoes from snow/ice and ice/water interfaces wereclearly detected. The snow depth and ice thickness measured by this radar system showed good
agreements with direct measurements [Uratsuka et al. 1989].
A short pulse radar with a pulse width of 1 ns at 4.3 GHz was developed to detect crevasses infront of a snowmobile. A preliminary experiment to measure the distance of plywood boards
was made in an anechoic chamber to confirm the fundamental characteristics of the radar.
Another experiment to detect a hole dug in the snow pile was made to find out the usefulness of
the radar for the crevasse detection [Suitz et al. 1989, Suitz and Uratsuka, 1990].

F2.4. Land, Vegetation and Others
In order to investigate the millimeter-wave scattering properties of various natural and manmade objects, two different types of experimental scatterometers were developed; a 50 GHz cw
scatterometer and a 60 GHz polarimetric step-frequency scatterometer [Awaka et al., 1989;
Ihara et al., 1991b]. Using the 60 GHz scatterometer, the backscattering coefficients of soil
surfaces were measured for different surface roughness conditions. The surface roughness wasmeasured with a laser profile meter. The incidence angle dependence of the measured
backscattering coefficient showed distinctive features according to the surface roughness. The
results are compared with estimates from a small perturbation theory [Yamasaki et al., 1991;
1992].

An active reflector for SAR calibration, in which the frequency of a received SAR signal was
shifted by a certain amount, was proposed. This frequency shift caused a shift of the reflector
image in azimuth direction. This function would allow to enhance a signal-to-clutter ratio of theimage by moving it onto a radiometrically dark background, and hence it would be possible touse a relatively narrow test site near water surface for SAR calibration [Fujita, 1992].
Dependence of SIR-B image intensity on local incidence angle was investigated to estimate
quantitatively topographic effects on SAR imagery. Slope images representing the variation of
local incidence angles of a hilly area were compared with the SIR-B images. Based on the
topographic effects, backscattering coefficients of the hilly area were estimated and comparedwith the existing data base [Satake et al., 1992].
(T. Manabe)

F3. Radio Communication
F3.1. Terrestrial Fixed Radio Systems
A new type of passive reflector which can reduce influences of the incident angle fluctuation
was presented [Komai, 1991].
The line-of-sight propagation test was carried out on three paths along the seashore in the southpart of Ghana using FM microwave radio-relay-link [Yoshikawa et al., 1992].
Several types of diversity systems were examined both theoretically and experimentally.
Propagation tests on tilted beam diversity were carried out on several paths. Test results showed
its effectiveness on a path with strong reflection [Satoh and Sasaki, 1989].
An prediction method for space diversity improvement was presented. This method was clarified
by world wide data [Hosoya, 1990]. A frequency diversity was effective to improve thetransmission quality on a path with strong reflection. Its effect in multi-carrier digital radio
system was newly clarified [Ichikawa and Murase, 1990]. An estimation formula of the received
power space correlation coefficient, which was necessary for designing the space diversity
reception system on microwave links, was obtained from amplitude statistics of three rays, pathconditions, radio meteorological statistics and so on [Sasaki et al.,1991a]. Multiple diversity
reception techniques were summarized including test results of both tilted beam and threeantenna diversities [Sasaki et al., 1991b].
A method for estimating the low path visibility is necessary to design a point to multi-point
radio communication system which uses mm-wave. The low path visibility can be estimated byusing building density, building height distribution and so on [Satoh and Ogawa, 1990].
(E. Ogawa)F3.2. Fixed Satellite Radio Systems
As for rain attenuation prediction methods, a concept on equivalent slant path was presented andwas given by a function of the elevation angle and the point rain rate, and determined using the

CCIR rain attenuation data bank so as to attain the minimum mean-square logarithmic error.
The prediction accuracy obtained was comparable to the best one so far presented [Irie, 1990].
Based on the current CCIR data bank on slant path attenuation, a similar formula to the existing
CCIR method which covers time percentages of 1.0 to 0.001% was proposed with improved
accuracy and expanded application range to 0.0001% [Irie, 1992]. A more improved prediction
method characterized by adopting an empirical relation between ratio of rain attenuation for
0.01% of time to that of 0.1% and ratio of rain rate for 0.01% to that for 0.1% was presented[Karasawa and Matsudo, 1990a]. A noticeable improvement of prediction accuracy could beobtained.
Moreover, a countermeasure of rain attenuation by means of onboard resource sharing (ORS)
based on dynamic rain information obtained by the AMeDAS data was proposed. Quantitativeevaluation of effective rain attenuation effect was conducted a computer simulation [Matsudo etal., 1992]. The effect of the cross-band frequency diversity was evaluated by considering a joint
outage probability based on the rain attenuation [Ogawa, 1989]. A method was proposed for the
mitigation of attenuation effect on satellite broadcasting systems that use higher frequency
bands, by using the time-diversity method. In this method, all of or part of the information wastransmitted several times, with certain time delay between each transmission. In order toevaluate the diversity effect, attenuation data at 19.5GHz measured in Japan were statisticallyanalyzed [Fukuchi, 1992a].
Since a continuous measurement system of G/T for a long period is needed to examine theperformance of BS receiving systems due to the weather effects, the whole measurement
parameters must be measured, controlled and processed by a computer automatically. The
development of such measurement system which can measure one or more receiving systems
was performed by using a noise estimation method [Purwanto et al., 1992a; b].
In the case of earth-space paths, it was found that there is poor correlation between measured
attenuation and XPD because of ice depolarization. This implies XPD prediction error if thetheoretical relationship between rain attenuation and XPD is used. A new method of predicting
cumulative distributions of XPD taking the ice effect into account by using the factor of 'icedepolarization ratio' was proposed [Fukuchi, 1990]. The applicability of this method wasverified by the experimental results. Testing of XPD prediction methods proposed so far was
carried out, and quantitative accuracy evaluations were conducted [Yamada and Karasawa,
1990]. The effect of XPD compensation at 4 and 6 GHz through a long-term measurement byusing the Intelsat-V satellite was analyzed [Yamada et al., 1990].
(Y. Karasawa)F3.3. Land Mobile Radio System
A small-section median field strength was measured on the line-of-sight paths in mountaineous
area using 280 MHz band. Field strength was around 2 dB-13 dB lower than that of free space[Morita and Nakano, 1989a]. A 280 MHz band regression equation in the mountainous area wasgiven from the relation between measured data and calculation results with knife-edge
diffraction model. Mountain diffraction losses were also calculated [Morita and Nakano,
1989b].
A prediction method for mobile propagation loss in urban environments was derived fromexperiments in Tokyo area. This method was applicable from 450MHz to 2200MHz band
[Sakagami and Akeyama, 1991]. By using statistical simulation, formulas for estimating mean

propagation loss in terms of base station antenna height, mobile station antenna height, meanbuilding height, mean distance between adjacent buildings and propagation path length wereobtained for frequencies of 400, 900, 1500, and 2000 MHz bands [Morita et al., 1991].
Delay profiles were measured in Koganei city, which included both urban and rural areas, andthe characteristics of the incident angle of the delayed waves were evaluated by using Doppler
spectrum analysis [Ohgane et al., 1991]. The results showed the difference between urban andrural areas. Measurement of delay profile characteristics in the 1.5 GHz band were carried out
within a 2 x 1.5 km area in the Tokyo metropolitan area. Measurements in the 775 MHz and 2.3
GHz bands were carried out for comparison with those of the 1.5 GHz band. In theexperimental results, the influence of obstacles on the average excess delay was almost the samein the three frequency bands. For the 1.5 GHz band, the mean value of delay spread was 3.0 ms,
and in 90 percent of the area it did not exceed 3.9 ms [Sekizawa et al., 1991]. Microcellular
multipath characteristics was measured in dense urban [Moriyama et al., 1991], residential[Moriyama et al., 1992c], and indoor environment [Moriyama et al., 1992d]. For dense urban
environment, delay spread in microcellular was smaller than for high base station antenna heightcase. Delay profile shapes observed in most of line of sight area was well fit to the exponential
model in dense urban and indoor case, whereas residential, hence echos come from distantbuilding made a ray having large excess delay, the exponential model was not valid.
Measurements for urban microcellular systems when the base-station antenna was mounted
below surrounding building heights were made at 1.5 GHz and 2.6 GHz. To determine thedominant rays of line-of-sight propagation characteristics, simple theoretical estimation using
geometrical techniques was reported [Iwama et al., 1992]. The total predicting method for
propagation characteristics was ale reported. A prediction model were based on a direct ray,specularly reflected rays, diffracted rays and successive combination of reflected and diffracted
rays. First, diffracted rays were calculated by knife-edge diffraction theory [Iwama et al., 1990].
Recently, diffracted rays were calculated by geometrical theory of diffraction (GTD) [Iwama
and Mizuno, 1992].
A modified classification of variations of indoor propagation was proposed based on the feasible
diversity techniques, and propagation characteristics using amplitude distributions wereconsidered [Mizuno et al., 1990]. As a result, short fading, whose period off variation was lessthan 1.5 wavelength was caused by multipath only, while long fading, whose period was longer
than 1.5 wavelength was caused by both multipath and shadowing.
A simple calculation method for worst delay spread caused by reflection obstacles such asbuilding, tower and mountain was derived by considering 2-ray model in mobile propagation[Ooi et al. 1990]. The propagation model and delay profile classification were proposed in orderto predict delay spread [Tanaka and Akeyama, 1990]. A propagation model was proposed thatcan be used to predict delay spread for mountain cities bordered by tall mountains [Tanaka etal., 1990]. Considering the generation mechanism of the fading in land mobile multipath
channels, and two kinds of fading (flat fading and frequency selective fading) weredistinguished by phenomenon [Ohgane and Sekizawa, 1991].
An experiment showed that the delay spread was effectively reduced by base station antenna
beam tilting in urban areas [Kozono and Takeuchi, 1991]. Propagation test results whichshowed effects of the delay spread on p/4-shift QPSK were reported [Oyama et al., 1992].
Narrowing and tilting of base station antenna beam were examined by theoretical andexperimental methods. As a result, the effectiveness in reducing the delay spread was confirmed[Tanaka et al., 1992].
In digital mobile-radio communication systems, to understand the effect of frequency selective
fading is very important for assessment of digital transmission characteristics in terms of delay

profile, delay spread and correlation bandwidth. For this purpose, a general model forcorrelation analysis in Nakagami-Rice fading conditions which include Rayleigh fading wasdeveloped [Karasawa et al., 1992]. Using this model, the frequency correlation characteristics intypical line-of-sight environments were analyzed. As a multiple access system in future mobile
communications, CDMA (code division multiple access) was attracted. For the analysis of nearfar problem of CDMA, a wideband fading model characterized by its algorithm applicable tocomputer simulation was developed [Iwai et al., 1992].
Compared results between wide band and narrow band signals were reported. It showed thereceived level distribution dependence on band width [Kozono et al., 1990]. Correlation
bandwidth in urban mobile radio path was measured and the relation between the bandwidthand propagation parameters was clarified [Sakagami and Kuboi, 1991a]. Recent propagation
studies on land mobile radio in Japan was summarized. It also includes propagation studies onland mobile satellite communication systems [Kozono et al., 1991].
In mobile radio environments, the mean effective gain of mobile antennas was analyzed andverified by measurements in actual urban areas [Taga, 1990a]. A measurement method of crosspolarization power ratio was proposed. Estimation of the measurement error showed that themethod had high accuracy [Taga, 1990b]. Considering the cross polarization power, thecorrelation characteristics of antenna diversity was analyzed. Measured results in urban areas
were agreed well with the calculated ones [Taga, 1990c].
Spatial correlation characteristics of mobile base station antennas was studied by measuring theangle-of-arrival in urban areas [Akeyama et al., 1990b]. A dual antenna experiment was
conducted in a Tokyo area to estimate the angular distribution of received waves in the mobile
radio environment as a function of position and delay time at 2.3 GHz [Thomas et al., 1992].
The results showed that the proposed algorithm was applied to real propagation situation.
The relationship between the bit error rate and multipath was studied only when the excess
delay of the multipath was enough smaller than the bit length of transmission signal. In theevaluation of bit error rate for the case when the excess delay of multipath fading was larger
than the bit length, the power of the delayed wave must be considered in addition to the delay
spread [Sekizawa et al., 1992].
A method to improve the delay resolution of delay profiles measured by the PN correlation
method was proposed [Manabe and Takai, 1992], and was applied to the analysis of indoor
radio propagation at 900 MHz and 2.3 GHz [Takai and Manabe, 1991]. Using the highresolition method, delay profile and directional dependence were measured in indoor multipath
environments[Matsui, 1992]. Design and implementation of macro cell multipath measurement
and reproduction equipments for land mobile radio was developed. With the help of antenna
switching controller, the equipment can store data measured by multiple antennas on verticaland horizontal [Moriyama et al., 1992a]. Microcellular multipath measurement equipment
having a time resolution of 40 ns was developed. For noise reduction of wideband received
signal, real-time averaging by coherent addition was implemented [Moriyama et al., 1992b].
Vehicle positions in multipath environments were estimated from the angle of arrival of waves
received by multibeam antennas installed at two base stations. The estimated root mean squareposition error was about 350m [Sakagami et al., 1992].
In Japan, a project to explore the millimeter-wave high-speed indoor communication system hasrecently started. The project includes studies on indoor multipath propagation, anti-multipath
techniques, and integrated antenna technology at millimeter-wave band. At its first stage, a 60GHz wideband channel sounder with a delay-time resolution of about 2 ns was developed [Ihara
et al., 1992]. The complex refractive index of soda-lime glass which was commonly used aswindow glass was measured at 60 GHz by a free-space reflection method [Manabe et al., 1992].
A platform, powered by microwaves beamed from the earth, carrying radio equipment andflying in the stratosphere, could be used for radio relay like satellite communications, terrestrial
microwave radio relay, land mobile base stations. In the Communications Research Laboratory,
applications of the high altitude radio platform (HARP) to telecommunications and remotesensing were studied. Features of mobile radio using the HARP, service coverage of the HARP
and cellular configurations were described [Saruwatari, 1990].
Using the method of moment and the wire-grid model, a thin planer antenna performances for acard-sized paging receiver, for example, the polarization switching system, the radiation
efficiency versus antenna height, and so on [Ishii and Itoh, 1991] and the wire-grid model
performance for the wire radii and grid geometry were estimated [Ishii and Itoh, 1992].
It was shown that the parallel-plate waveguide modes supported by the slot and the reflector
had a harmful influence on antenna characteristics such as drastical changes of the radiation
efficiency, and input impedance due to the generation of higher harmonic parallel-platewaveguide modes, by using Galerkin's method in spectral-domain [Katsurahara et al., 1992].
The superresolution technique for the time-domain measurements was proposed. Experimental
results of the semirigid cable with a dummy illustrate that it has much better capability ofresolving signals and analyzing parameters (e.g. reflection coefficient) comparing with the FFT
and gating technique [Ogawa et al., 1990]. Especially, the MUSIC (MUltiple SIgnal
Classification) - MSSP (Modified Spatial Smoothing Preprocessing) reveals outstanding
performance. And it is mentioned the effect of frequency dependent reflections and distributed
reflections [Yamada et al., 1991]. This technique can be used for the antenna measurements andscattering studies [Ogawa et al., 1991]. The generalized matrix formula for scattering
mechanism extraction was derived for diffraction coefficient estimation of each scattering centerwith narrow frequency bandwidth data [Yamada et al. 1992]. Furthermore, the MUSIC
algorithm accompanied with the FFT and gating techniques for improving signal-to-noise ratio
can saves the number of snapshots, then it can be useful especially for antenna patternmeasurements [Ogawa et al., 1992b].
It reviewed four basic adaptive antenna theories, an LMS adaptive antenna reduced theinterference signals by minimizing the square error. A DCMP adaptive antenna and a HowellsApplebaum adaptive antenna were used when the arrival direction of the desired signal was
known at a receiver. A power inversion adaptive antenna can be used for cancelling very strong
interference signals [Ogawa and Kikuma, 1992]. Complex weights were determined by asample matrix inverse method. Namely, a correlation matrix and correlation vector estimate
using training symbols, and then the optimum complex weights obtained directly solving
simultaneous equations. This method solved the convergence problem inherent in the adaptivearray based on the conventional gradient techniques [Ogawa et al., 1992c]. Training codes used
for the reference signal which was known at a receiver. After the training period, detected codesuse for the reference signal. It showed the proper behavior of the LMS adaptive array with theabove reference signal generator in computer simulations. In addition to the multipath fading
reduction, we can improve a signal-to-noise ratio by the diversity technique [Ogawa et al.,1992a].
Recently, a new architecture for adaptive array antenna was proposed. The basic function wasformulated as a recursive least squares minimization operation under the condition of the linear
direction constraint. This algorithm can be implemented using a pipelined architecture in theform of a triangular systolic array processor (SAP). This paper presented interference andmultipath suppressions of adaptive array antenna with SAP in several signal environments using
numerical simulation and then discusses them [Ohmiya et al., 1992a; b].

(E. Ogawa)F3.4. Mobile Satellite Radio Systems
As for multipath fading due to sea surface reflection in maritime mobile satellite systems(MMSS), a new model for analysis of frequency correlation statistics was presented [Karasawa,
1989]. Using this model, various transmission path models such as three- and four-path models
were proposed. Various kinds of diversity techniques for multipath fading reduction were
examined taking the correlation characteristics, such as space correlation and frequency
correlation, into account [Yasunaga et al. 1989]. Effects of 1.5GHz multipath propagation overthe sea and land in aeronautical mobile-satellite systems (AMSS) were analyzed [Karasawa etal., 1990]. For some parameters, validity of theoretical estimates was examined throughcomparison with experimental data obtained aboard a helicopter. A simple prediction method ofmultipath fading due to sea surface scattering for MMSS and AMSS for engineering application
was developed [Yasunaga and Karasawa, 1990]. The method was evaluated by the theory andmeasured data reported so far, and the good accuracy over wide range of parameters was
identified. A new fading reduction scheme for sea surface reflection applicable to Inmarsat-C
was proposed [Iwai et al., 1991]. This method combined with an open-loop space diversity,
forward error correction scheme (FEC) and an interleaver overcomes disadvantages generally
associated with a conventional diversity system.
Concerning inter-satellite interference evaluation, effect of propagation when both wanted wave
and unwanted wave are affected by multipath fading must be very important. For this purpose,a rigorous theoretical method for predicting C/I and C/(N+I) where both C and I are in
Nakagami-Rice fading conditions was presented [Karasawa and Yasunaga, 1992]. Analternative simple prediction method which is more suitable for engineering application wasthen proposed. Prediction errors of the simple method was evaluated by using the ETS-V
experimental data.
In land mobile satellite communications, signals to and from a satellite are affected bysurrounding features such as buildings, trees, terrains and so on. Experimental and theoretical
discussions on amplitude and phase variations of received signals when a land vehicles passing
near a utility pole were presented [Tanaka et al., 1990].
(Y. Karasawa)

References
Adachi, T., T. Tsuda, Y. Masuda, S. Fukao and S. Kato, Dependence of temperature accuracyof RASS on a ratio between radar and acoustic pulse lengths, in Proc. Lower Tropospheric
Profiling: Needs and Tech., Boulder, USA, 41-42 (1991)
Akeyama, A., S. Sakagami and K. Yosizawa, Propagation characteristics of air-ground paths,
900MHz Band, Trans. IEICE Japan, J73-B-ll,.8, 383-389 (1990a), (in Japanese)
Akeyama, A., S. Sakagami and S. Aoyama, UHF band spatial correlation characteristics ofmobile base station antennas, Trans. IEICE Japan, J73-B-ll, 12, 838-842 (1990b), (in Japanese)Awaka, J., T. Ihara and K. Okamoto, Development of millimeter wave scatterometers, Rev.
Comm. Res. Lab., 35, 535-543 (1989), (in Japanese)
Awaka, J., E. Kawai, T. Ihara, K. Kitamura, Y. Echizen'ya and K. Okamoto, Millimeter andoptical wave propagation experiments under snow, fog, and rain conditions at Akita, J. Comm.
Res. Lab., 38, 645-659 (1991)
Awaka, J., Attenuation and backscatter properties of bright-band computed at 13.8 GHz, Proc.
1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan, 1057-1060 (1992)
Fujita, M., Influence of scattering from rough ocean surface on rain measurements withmicrowave radiometry, J. Electromag. Waves Appl., 5, 1089 - 1103 (1991)
Fujita, M., An active reflector for SAR calibration having a frequency shift capability, Trans.
IEICE Japan, E75-B, 791-893 (1992)
Fukao, S., Y. Maekawa, Y. Sonoi and F. Yoshino, Dual polarization radar observation ofthunderclouds on the coast of the Sea of Japan in the wintertime, Geophys. Res. Lett., 18, 179182 (1991a)
Fukao, S., G. Kotani, M. D. Yamanaka, T. Sato, Y. Maekawa, H. Uyeda, A. Sumi, A.
Watanabe, T. Tsuda and S. Kato, Mu radar observations of hierarchical structures of the Baiu
front, Proc. Fifth Int. Workshop on MST radar, Wales, UK, 49-51 (1991b)
Fukuchi, H., Prediction of depolarization distribution on earth-space path, IEE Proc., pt. H, 137,
6, 325-330 (1990)
Fukuchi, H., Slant path attenuation analysis at 20GHz for time-diversity reception of futuresatellite broadcasting, Proc. URSI-F Open Symp., Ravenscar, UK, 6.5.1-6.5.4 (1992a)
Fukuchi, H., Effects of integration time on rain attenuation statistics at 20 GHz, Proc. 1992 Int.
Symp. Antennas and Propagat. (ISAP'92), Sapporo, Japan, 1081-1084 (1992b)
Hatanaka, M., M. Hikichi and A. Nishitsuji, A basic consideration for remote sensing using
microwave radars on a satellite, Proc. Pacific Ocean Rem. Sens. Conf., 721-726 (1992)
Hayashi, T., T. Nishimura, T. Takano, Z. Yamamoto, M. Yamada, K. Shuto, H. Saito, T.
Ichikawa, N. Kawashima, E. Mizuno, S. Oh-hashi, S. Betsudan, D. Sweetnam and E. R.
Kursinski, Radio science experiment of Voyager-2 spacecraft occultation by Neptune, Proc.
17th Int. Symp. Space Tech. Sci, 1929-1934 (1990)
Hisaki, Y., Remote sensing of sea states by HF radar, J. Remote Sensing Soc. Japan, 12, 1, 8891 (1992), (in Japanese)
Hisaki, Y. and M. Tokuda, Measurement of wave parameters by HF ocean radar, Proc. Pacific
Ocean Rem. Sens. Conf., 53-58 (1992)
Hosoya, Y., An unified prediction method for space diversity improvement in received power on
microwave links, Trans. IEICE Japan, J73-B-II, 12, 869-875 (1990), (in Japanese)
Ichikawa, H. and T. Murase, Frequency diversity effects in multi-carrier digital radio systems,
Trans. IEICE Japan, J73-B-II, 8, 349-356 (1990), (in Japanese)
Iguchi, T., T. Umehara, Y. Ohno and K. Nozaki, Effect of T/R switching sequence for an HF
ocean radar, in T. Suzuki, H. Ogura, and S. Fujiwara (ed.), IEICE Japan, Proc. 1989 Int. Symp.

Noise Clutter Rejection Radars Imaging Sensors, Kyoto, Japan, 33-36 (1989)
Iguchi, T., Measurements of sea backscatter at extremely low grazing angles by a C-band
Doppler radar, J. Comm. Res. Lab., 36, 149, 157-169 (1989)
Iguchi, T., T. Umehara and Y. Ohno, HF radar measurements of ocean currents and sea state,
Sea and Sky, 66, 3, 39-54 (1990), (in Japanese)
Iguchi, T., HF ocean radar -- Principles of the ocean radar, Rev. Comm. Res. Lab., 37, 3, 345360 (1991a), (in Japanese)
Iguchi, T., HF ocean radar -- On the transmit/receive switching wave form for FMICW HF
ocean radar, Rev. Comm. Res. Lab., 37, 3, 361-374 (1991b), (in Japanese)
Iguchi, T., HF ocean radar -- HF ocean radar measurements of waveheight, Rev. Comm. Res.
Lab., 37, 3, 417-427 (1991c), (in Japanese)
Ihara, T., K. Okamoto, T. Kozu, J. Awaka, K. Nakamura and M. Fujita, Development of key
devices for TRMM rain radar, Proc. IGARSS'91, Espoo, Finland, 513-516 (1991a)
Ihara, T., J. Awaka, K. Okamoto, H. Yamasaki and A. Takahashi, Development of millimeterwave scatterometers, J. Comm. Res. Lab., 38, 661-677 (1991b)
Ihara, T., T. Manabe, M. Mizuno, H. Ryuko and K. Sato, Development of a 60-GHz indoor
propagation experimental system with a fine delay-time resolution, Proc. Int. Symp. Antennas
Propagat. (ISAP'92), Sapporo, Japan, 401-404 (1992)
Irie, K., Prediction of one-minute rain rate statistics for rain attenuation, Trans. IEICE Japan,
J72-B-II, 10, 577-579 (1989), (in Japanese)Irie, K., An empirical prediction model for rain attenuation in satellite communications, Trans.
IEICE Japan, J73-B-II, 10, 554-558 (1990), (in Japanese)Irie, K., A formula for cumulative time probability distribution of slant-path rain attenuation,
Trans. IEICE Japan, J75-B-II, 3, 211-214 (1992), (in Japanese)
Ishii, N. and K. Itoh, Analysis on small planer antenna in a paging system, Trans. IEICE Japan,
E74, 10, 3233-3240 (1991)
Ishii, N. and K. Itoh, A consideration on the thin planer antenna analysis with wire-grid model,
Proc. 1992 Int. Symp. Antenna Propagat. (ISAP'92), Sapporo, Japan, 441-444 (1992)
Ito, S. and T. Oguchi, Approximate solutions of the vector radiative transfer equation for
linearly polarized light in discrete random media, J. Opt. Soc. Am. A, 6, 12, 1852-1858 (1989)
Iwai, H., M. Yasunaga and Y. Karasawa, A fading reduction technique using interleave-aided
open loop space diversity for digital mobile-satellite communications, Trans. IEICE Japan, E74,
10, 3286-3294 (1991)
Iwai, H. , Y. Karasawa and T. Shiokawa, Wide band channel model for the analysis of near-far
problem in CDMA mobile radio, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo,
Japan, 89-92 (1992)
Iwama, T., E. Moriyama, H. Ryuko, S. Sekizawa and T. Saruwatari, Investigation of
propagation characteristics above 1GHz for microcellular land mobile radio, Proc. 40th IEEE

Veh. Technol. Conf., Orlando, Florida, USA, 396-400 (1990)
Iwama, T., E. Moriyama, S. Sekizawa, H. Ryuko, M. Mizuno and T.Saruwatari, Prediction ofline-of-sight propagation characteristics above 1 GHz for microcellular land mobile radio, Rev.
Comm. Res. Lab., 39, 3, 165-172 (in Japanese), (1992)
Iwama, T. and M. Mizuno, Prediction of propagation characteristics for microcellular land
mobile radio, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan, 421-424(1992)
Karasawa, Y., Complex frequency correlation characteristics of L-band multipath fading due tosea surface scattering, Trans. IEICE Japan, J72-B-II, 12, 633-639.(1989), (in Japanese)
Karasawa, Y. and M. Yamada, Prediction on statistics for tropospheric scintillations on Earthspace paths, Proc. URSI 23rd General Assembly, Prague, Czechoslovakia, 569 (1990)
Karasawa, Y., M. Yasunaga, T. Shiokawa and M. Yamada, Propagation characteristics foraeronautical mobile-satellite systems, AIAA 13th Int. Comm. Sat. Sys. Conf., Los Angeles,
USA, 575-582 (1990)
Karasawa, Y. and T. Matsudo, More improved prediction method for rain attenuation on Earthspace paths, Trans. IEICE Japan, J73-B-II, 1, 27-33 (1990a), (in Japanese)
Karasawa, Y. and T. Matsudo, A prediction method of one-minute rain rate distribution in
Japan, Trans. IEICE Japan, J73-B-II, 10, 518-527 (1990b), (in Japanese)
Karasawa, Y. and T. Matsudo, Statistics of one-minute rain rate distributions in Japan based on
AMeDAS one-hour rain rate data, IEEE Trans. Geosci. Rem. Sens., 29, 6, 890-898 (1991)
Karasawa, Y. and M. Yasunaga, Interference evaluation method for mobile-satellite
communications under Nakagami-Rice fading conditions, Trans. IEICE Japan, E75-B, 1, 42-49(1992)
Karasawa, Y., H. Iwai and T. Shiokawa, Modeling of frequency correlation characteristics forline-of-sight mobile radio systems, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92),
Sapporo, Japan, 429-432 (1992)
Katsurahara, K. and K. Itoh, Theoretical consideration on parallel-plate waveguide modes of aslot antenna with a reflector, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo,
Japan, 437-440 (1992)
Kawaguchi, Y., Long-distance propagation in a stratified atmosphere with an even power N
profile, Trans. IEICE Japan, J75-B-II, 6, 379-388 (1992), (in Japanese)
Komai, T., Passive reflector to reduce fading due to angle-of arrival variation on microwave
links, Trans. IEICE Japan, J74-B-II, 8, 447-453 (1991), (in Japanese)
Kozono, S. and T. Tanaka, Received level characteristics of wide band signal in mobile
communications, Trans. IEICE Japan, J73-B-ll, 6, 313-315 (1990), (in Japanese)
Kozono, T. and T. Takeuchi, Recent propagation studies on land mobile radio in Japan, Trans.
IEICE Japan, E 74, 6, 1538-1546 (1991)
Kozono, S., S. Aoyama and T. Tanaka, Prediction of propagation delay spread in mobile radio
communications, IEEE AP-S Digest, 3, 1548-1551 (1991), (in Japanese)

Kozu, T., Effects of return-signal decorrelation on pulse-compression properties for nadir
looking spaceborne radar, Proc. IGARSS'90, College Park, USA, 2073-2076 (1990)
Kozu, T., K. Nakamura, R. Meneghini and W. C. Boncyk, Dual-parameter rainfall
measurements from space: experimental test with an airborne radar system, Proc. 17th Int.
Symp. Space Tech. Sci., Tokyo, Japan, 1965-1970 (1990)
Kozu, T., Effects of signal-decorrelation on pulse-compressed waveforms for nadir-looking
spaceborne radar, IEEE Trans. Geosci. Rem. Sens., 29, 786-790 (1991)
Kozu, T. and K. Nakamura, Rainfall parameter estimation from dual-radar measurements
combining reflectivity profile and path-integrated attenuation, J. Atmos. Oceanic Technol., 8,259-270 (1991)
Kozu, T., K. Nakamura and R. Meneghini, Estimation of raindrop size distribution parametersfrom a dual-parameter spaceborne radar measurement, Preprints 25th Conf. Radar Meteor.,
Paris, Amer. Meteor Soc., 384-387 (1991a)
Kozu, T., K. Nakamura, R. Meneghini and W. C. Boncyk, Dual-parameter radar rainfall
measurement from space: a test result from an aircraft experiment, IEEE Trans. Geosci. Rem.
Sens., 29, 690-703, (1991b)
Kozu, T., M. Kojima, K. Oikawa, K. Okamoto, T. Keating and H. P. Cline, The development of
Tropical Rainfall Measuring Mission (TRMM), Proc. 18th Int. Space Technol. Sci., Kagoshima,
Japan, 1285-1290 (1992a)
Kozu, T., M. Kojima, K. Oikawa, K. Okamoto, T. Ihara and T. Manabe, Development status ofrain radar for Tropical Rainfall Measuring Mission, Proc. IGARSS'92, Houston, USA, (1992b)
Kumagai, H., R. Meneghini and T. Kozu, Multi-parameter airborne rain radar experiment in theWestern Pacific, Proc. 25th Int. Conf. Radar Meteorol., Paris, France, 400-403 (1991)
Kumagai, H., R. Meneghini and T. Kozu, Hydrometeor discrimination in melting layer using
multiparameter airborne radar measurement, Proc. Int. Geosci. Rem. Sens. Symp., Houston,
USA, 1725-1727 (1992a)
Kumagai, H., R. Meneghini, T. Kozu and K. Okamoto, Airborne radar radiometermeasurements of tropical storms, Proc. 18th Int. Symp. Space Technol. Sci., Kagoshima, Japan,
1977-1982 (1992b)
Kuroiwa, H., Y. Ohno, Y. Hisaki and A. Nadai, HF ocean radar system at Okinawa Radio
Observatory, Proc. Pacific Ocean Rem. Sens. Conf., 47-52 (1992)
Liebe, H. J., T. Manabe and G. A. Hufford, Millimeter-wave attenuation and delay rates due tofog/cloud conditions, IEEE Trans. Antennas Propagat., 37, 1617-1623 (1989)
Liebe, H. J., G. A. Hufford and T. Manabe, A model for the complex permittivity of water at
frequency below 1 THz, Int. J. Infrared and Millimeter Waves, 12, 659-675 (1991)
Maekawa, Y., N. S. Chang, A. Miyazaki and T. Segawa, Effects of ice depolarization on Kaband satellite-earth path in stratus rainfall events, Electron. Lett., 26, 2006-2007 (1990a)
Maekawa, Y., N. S. Chang, A. Miyazaki and T. Segawa, Characteristics of depolarization
fluctuation of Ka-band satellite beacon with small attenuation, Proc. AP-S/URSI Int. Symp.,
Dallas, USA, 4, 1812-1815 (1990b)

Maekawa, Y., N. S. Chang, A. Miyazaki and T. Segawa, Calculation of depolarization
cancellation on Ka-band satellite-to-ground path, Proc. AP-S/URSI Int. Symp., London,
Ontario, Canada, 3, 1560-1563 (1991a)
Maekawa, Y., S. Fukao, M. Yamamoto, T. Tsuda, M. D. Yamanaka, T. Nakamura, S. Kato and
R. F. Woodman, High-altitude-resolution observation of the upper stratosphere using
Jicamcarca VHF radar, Proc. Fifth Int. Workshop on MST radar, Wales, UK, 116-121 (1991b)
Maekawa, Y., S. Fukao, Y. Sonoi and F. Yoshino, Dual polarization radar observation of
wintertime thunderclouds in Japan, Proc. IGARSS'91, Espoo, Finland, 2, 505-508 (1991c)
Maekawa, Y., N. S. Chang, A. Miyazaki and T. Segawa, Rapid changes in depolarization due tothunderclouds obtained from CS-3 beacon signal observation, Proc. AP-S Int. Symp., Chicago,
USA, 2, 744-747 (1992a)
Maekawa, Y., N. S. Chang, A. Miyazaki and T. Segawa, Rain depolarization characteristics
related to rainfall types, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan,
1041-1044 (1992b)
Maekawa, Y., N. S. Chang and A. Miyazaki, Rain depolarization characteristics related toapproximated specific attenuation, Electron. Lett., 28, 1557-1558 (1992c)
Maekawa, Y., S. Fukao, M. Yamamoto, M. D. Yamanaka, T. Tsuda, S. Kato and R. F.
Woodman, Upper stratospheric vertical winds observed by the Jicamarca VHF radar, Proc. Int.
Symp. Middle Atmos. Sci (MAS Symp.), Kyoto, Japan, 151-152 (1992d)
Maekawa, Y., S. Fukao, Y. Sonoi and F. Yoshino, Dual polarization radar observations ofanomalous wintertime thunderclouds in Japan, IEEE Trans. Geosci. Rem. Sens., 30, 838-844(1992e)Manabe, T., T. Ihara and K. Okamoto, Effects of surface clutter on rain measurements from theTropical Rainfall Measuring Mission Satellite, Proc. 1989 Int. Symp. Noise Clutter Rejection
Radars Imaging Sensors, Kyoto, Japan, 263-268 (1989)
Manabe, T. and H. Takai, Superresolution of multipath delay profiles measured by PN
correlation method, IEEE Trans. Antennas Propagat., 40, 500-509 (1992).
Manabe, T., K. Sato and T. Ihara, Measurement of complex refractive index of soda-lime glassat 60 GHz by vector-network-analyzer-based scatterometer, Electron. Lett., 28, 1354-1355(1992)
Masuda, Y., J. Awaka, K. Okamoto, T. Tsuda, S. Fukao and S. Kato, Echo power loss withRASS (Radio Acoustic Sounding System) due to defocusing effects by distorted acoustic
wavefronts, Radio Sci., 25, 975-981 (1990)
Masuda, Y., J. Awaka, K. Nakamura, T. Adachi and T. Tsuda, Analysis of RASS using achirped acoustic waves, Radio Sci., 27, 681-691 (1992a)
Masuda, Y., K. Okamoto, K. Nakamura, T. Ihara, and T. Onishi, Development of a lower
atmosphere wind profiler and preliminary observation results, Rev. Comm. Res. Lab., 38, 15-33(1992b), (in Japanese)
Masuda, Y., T. Ihara, K. Nakamura, K. Okamoto and T. Onishi, Development of a lower
atmospheric wind profiler, J. Rem. Sens. Soc. Japan, 12, 43-56 (1992c), (in Japanese)

Matsudo, T., Y. Karasawa and T. Shiokawa, Rain attenuation compensation by onboard
resource sharing based on dynamic rain information from AMeDAS, IEICE Japan, Proc. 1992
Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan, 1073-1076 (1992)
Matsui, W., Directional dependence of indoor multipath propagation characteristics, IEEE AP-S
Digest, 1384-1387 (1992)
Meneghini, R., T. Kozu, H. Kumagai and W. C. Boncyk, Analysis of airborne radar andradiometer rain measurements and their relationship to spaceborne observations, Proc.
IGARSS'90, College Park, USA, 429-432, (1990)
Meneghini, R. and T. Kozu, A potential method for the estimation of drop size distribution froma dual-wavelength airborne radar. in Preprints, 25th Conf. Radar Meteor., Paris, Amer. Meteor.
Soc., 380-383, (1991)
Meneghini, R., T. Kozu, H. Kumagai and W. Boncyk, A study of rain estimation methods fromspace using dual-wavelength radar measurements at near-nadir incidence over ocean, J. Atmos.
Oceanic Tech., 9, (4), 364-382, (1992)
Miyazaki, A., N. S. Chang, Y. Maekawa and T. Segawa, Calibration of rain radar for satellite
slant path by ground based rain gauge, Trans. IEICE Japan, J73-B-II, 561-563 (1990), (inJapanese)
Mizuno, E., N. Kawashima, K. Oyama, T. Takano, S. Sasaki, Z. Yamamoto, J. Haruyama andG. Toriyama, Analysis of Voyager-Neptune radio science data acquired with Usuda Antenna,
Proc. 17th Int. Symp. Space Tech. Sci., 1935-1940 (1990)
Mizuno, E., N. Kawashima, T. Takano and P. A. Rosen, Voyager radio science: Observations
and analysis Neptune's atmosphere, IEICE Trans. Comm., 75, 7, 665-672 (1992)
Mizuno, M. and C. Bergljung, Characterization of indoor propagation using amplitude
distributions, J. Comm. Res. Lab., 37, 150, 29-35 (1990)
Morita, K. and T. Nakano, 280 MHz mobile field strength in mountaineous area of line-ofsight, Trans. IEICE Japan, J72-B-II, 10, 575-576 (1989a), (in Japanese)
Morita, K. and T. Nakano, 280 MHz band mobile field strength in mountaineous area, Trans.
IEICE Japan, J72-B-II, 12, 677-679 (1989b), (in Japanese)
Morita, K. and I. Higuti and S. Sato, Formulas for estimating mean propagation loss in UHFband urban mobile communications, Trans. IEICE Japan, J74-B-II, 6, 390-393 (1991), (inJapanese)Moriyama, E., M. Mizuno, Y. Nagata, Y. Furuya, I. Kamiya and S. Hattori, 2.6 GHz band
multipath characteristics for urban microcellular telecommunication systems, Proc. Int. Symp.
Personal, Indoor, and Radio Comm., London, UK, 347-352 (1991)
Moriyama, E., M. Mizuno, T. Iwama, T. Ohgane, H. Ryuko, and S. Sekizawa, Development ofmultipath measurement and simulation equipment for wideband mobile radio, Proc. 42nd IEEE
Veh. Tech. Conf., Denver, USA, 536-539 (1992a)
Moriyama, E., H. Tomita, and H.Misaizu, Development of multipath measurement equipment
for microcellular systems, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan,
397-400 (1992b)

Moriyama, E., M. Mizuno, Y. Nagata, Y. Furuya, I. Kamiya and S. Hattori, 2.6 band multipathcharacteristics measurement in a residential area for micro-cellular systems, Proc. 42nd IEEE
Veh. Technol. Conf., Denver, USA, 423-426 (1992c)
Moriyama, E., M. Mizuno, Y. Nagata, Y. Furuya, I. Kamiya and S. Hattori, 2.6 GHz multipathcharacteristics measurement in a shielded Building, Proc. 42nd IEEE Veh. Tech. Conf., Denver,
USA, 621-624 (1992d)
Nadai, A., Statistical Study of HF Ocean Radar Echo, Proc. of Pacific Ocean Rem. Sens. Conf.,
65-70 (1992)
Nozaki, K., HF ocean radar -- Configuration of the HF ocean radar system, Rev. Comm. Res.
Lab., 37, 3, 375-382 (1991), (in Japanese)
Ogawa, E., Cross-band frequency diversity effect for rain attenuation on earth-satellite paths,
Trans. IEICE Japan, J72-B-II, 12, 655-663 (1989), (in Japanese)
Ogawa, Y., H. Yamada, M. Ohmiya and K. Itoh, Time-domain measurements using a
superresolution technique, 1990 IEEE/AP-S Int. Symp. Digest, 4, 74-9, 1592-1595 (1990)
Ogawa, Y., H. Yamada and K. Itoh, A time-domain superresolution technique for antenna
measurements and scattering studies, 1991 IEEE/AP-S Int. Symp. Digest, 2, 86-8, 1198-1201(1991)
Ogawa, Y., Y. Nagashima and K. Itoh, An adaptive antenna system for high-speed digital
mobile communications, Trans. IEICE Japan, E75-B, 5, 413-421 (1992a)
Ogawa, Y., T. Nakajima, H. Yamada and K. Itoh, A superresolution technique for antenna
pattern measurements, IEICE Japan, Proc. 1992 Int. Symp. Antennas Propagat., 997-1000(1992b)Ogawa, Y. and N. Kikuma, Developments and prospects of adaptive antenna theories, Trans.
IEICE Japan, J75-B-II, 11, 721-732 (1992)
Ogawa, Y., T. Kawabata and K. Itoh, Multipath suppression using an adaptive array based on
an SMI method in high-speed digital land mobile communications, Trans. IEICE Japan, J75-BII, 11, 806-814 (1992c)
Oguchi, T. and S. Ito, Multiple scattering effects on the transmission and reflection of
millimeter pulse waves in rain, Radio Sci., 25, 3, 205-216 (1990)
Oguchi, T., Effects of incoherent scattering on microwave and millimeter wave communications
through rain, Electron Lett., 27, 9, 759-760 (1991)
Oguchi, T, N. Ishida and T. Ihara, Multiple scattering effects on the retrieval of rain-rate
profiles using dual-wavelength radar techniques, Memoirs Tokyo Metropolitan Inst. Tech., 6,39-45 (1992), (in Japanese)
Ohgane, T., S. Sampei, Y. Kamio, H. Sasaoka and M. Mizuno, UHF urban and suburban
multipath propagation characteristics in wideband mobile radio communications, Rev. Comm.
Res. Lab., 37, 1, 19-27 (1991), (in Japanese)
Ohgane, T. and S. Sekizawa, A review of the propagation characteristics in land mobile
communications, Rev. Comm. Res. Lab., 37, 1, 13-17 (1991), (in Japanese).

Ohmiya, M., T. Kawabata, Y. Ogawa and K. Itoh, Performance of an adaptive array antenna
with a systolic array processor, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo,
Japan, 141-144 (1992a)
Ohmiya, M., T. Kawabata, Y. Ogawa and K. Itoh, Multipath suppression performance of an
adaptive array antenna with a systolic array processor, Trans. IEICE Japan, J75-B-II, 11, 780788 (1992b)
Ohno, Y., HF ocean radar -- Observation of current on the south coast of Okinawa by the HF
ocean radar, Rev. Comm. Lab., 37, 3, 393-404 (1991a), (in Japanese)Ohno, Y., HF ocean radar -- HF ocean radar measurements of sea-surface wind, Rev. Comm.
Res. Lab., 37, 3, 429-435 (1991b), (in Japanese)Ohno, Y., HF ocean radar observation of ocean currents, J. Comm. Res. Lab., 38, 3, 377-385(1991c)Ohno, Y. and M. Tokuda, Kuroshio observation by the HF ocean radar, Proc. Pacific OceanRem. Sens. Conf., 59-64 (1992)
Ohsaki, Y., Error analysis of Zdr and rainfall rate on the measurements of dual-polarized rainradar by computer simulation, Proc. 25th Int. Conf. Radar Meteorol., Paris, France, 539-542(1991)
Ohsaki, Y., Error analysis of Zdr measurements from dual-polarized rain radar as a function ofpolarization switching time, J. Comm. Res. Lab., 39, 2, 421-436 (1992)
Ohsaki, Y. and M. Fujita, An intercomparison between MSR and SI retrieved rain rates, Trans.
IEICE Japan, E75-B, 5, 422-426 (1992)
Ojima, T., M. Maeda and H. Sato, Retrieval accuracy of water vapor content and bias-error
causes of the MSR aboard MOS-1, Proc. IGARSS'90, College Park, USA, 835 - 838 (1990)
Oka, E., Ray-tracing analysis of anomalous propagation through horizontally nonuniform
surface duct, Trans. IEICE Japan, J73-B-II, 1, 51-57 (1990), (in Japanese)
Okamoto, K. and T. Tanaka, Tropical Rainfall Measuring Mission (TRMM), Proc. 17th Int.
Symp. Space Tech. Sci., Tokyo, Japan, 1947-1952 (1990)
Okamoto, K., T. Ihara, T. Kozu, J. Awaka and K. Nakamura, Rain radar in the Tropical Rainfall
Measuring Mission, Proc. of URSI-F Special Open Symp. Regional Factors in Predicting
Radiowave Attenuation due to Rain, Rio de Janeiro, Brazil, 171-174 (1990)
Okamoto, K., T. Ihara, T. Kozu, K. Nakamura, J. Awaka and M. Fujita, Development status ofrain radar in the Tropical Rainfall Measuring Mission, Proc. 25th Int. Conf. Radar Meteorol.,Paris, France, 388-391 (1991a)
Okamoto, K., T. Kozu and K. Nakamura, TRMM rain radar and its rain rate retrieval, Proc.
Third Int. Conf. Precipitation Modeling, 15-18 (1991b)
Okamoto, K., T. Ihara and H. Kumagai, Development of bread board model of TRMM
precipitation radar, Proc. 18th Int. Symp. Space Technol. Sci., Kagoshima, Japan, 1919-1924(1992).
Ooi, T. and S. Kozono, Effect of a reflection obstacle on delay spread in mobile propagation,

Trans. IEICE Japan, J73-B-II, 5, 265-267 (1990), (in Japanese)
Oyama, H., M. Ikura, Y. Yamao and S. Kozono, Irreducible BER of p/4-Shift QPSK due todelay spread in real mobile propagation environment, Trans. IEICE Japan, J75-B-ll, 4, 255-257(1992), (in Japanese)
Purwanto, Y., Y. Ogawa, M. Ohmiya and K. Itoh, A continuous measurement of G/T forsatellite broadcasting receiving systems, Trans. IEICE Japan, E75-B, 8, 767-774 (1992a)
Purwanto, Y., Y. Ogawa and K. Itoh, A continuous measurement system of G/T for satellite
broadcasting receivers, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan,
681-684 (1992b)
Sakagami, S. and K. Kuboi, Mobile propagation loss prediction for arbitrary urban
environments, Trans. IEICE Japan, J74-B-ll, 1, 17-25 (1991), (in Japanese)
Sakagami, S. and A. Akeyama, Correlation bandwidth in urban mobile radio paths -dependence of distance, base station antenna height and average building height -- , Trans.
IEICE Japan, J74-B-ll, 1, 26-34 (1991), (in Japanese)
Sakagami, S., S. Aoyama, K. Kuboi, S. Shirota and A. Akeyama, Vehicle position estimates bymultibeam antennas in multipath environments, IEEE Trans. Veh. Tech., VT-41, 1, 63-68(1992)
Saruwatari, T., Feasibility study on radio communications using high altitude radio platform inthe stratosphere -- Applicability to mobile radio and coverage performance --, J. Comm. Res.
Lab., 37, 150, 29-35 (1990).
Sasaki, O., A. Satoh and Y. Hosoya, An investigation on the relation between radiometeorological parameters and microwave fading occurrence probability, Trans. IEICE Japan,
J73-B-II, 8, 449-452 (1990), (in Japanese)
Sasaki, O., A. Satoh and Y. Hosoya, An estimation formula of received power space correlation
coefficient using three-ray model, Trans. IEICE Japan, J74-B-II, 10, 507-514 (1991a), (inJapanese)
Sasaki, O., A. Satoh and Y. Hosoya, Multiple diversity reception techniques, NTT Rev. 3 , 1,
66-74 (1991b)
Satake, M., M. Fujita and N. Fugono, Analysis of topographic effects on SIR-B imagery:
Correlation of image intensity with local incidence angles, Trans. IEICE Japan, E75-B, 12201226 (1992)
Satoh, A. and O. Sasaki, Tilted-beam-, beam-width- and space-diversity improvements on
various paths, IEEE Globecom'89, 2.3.1-2.3.5 (1989)
Satoh, A. and E. Ogawa, An estimation method for low propagation path visibility and radiozone design in urban area, Trans. IEICE Japan, J73-B-II, 6, 293-300 (1990), (in Japanese)
Sekizawa, S. and E. Moriyama, 1.5 GHz band multipath propagation characteristics in an urban
area, J. Comm. Res. Lab., 38, 1, 101-106 (1991)
Sekizawa, S., H. Hanado and E. Moriyama, An experimental determination of the relationshipbetween bit error rate and multipath, Trans. IEICE Japan, J75-B-II, 4, 244-247 (1992), (inJapanese).

Short, D. A., T. Kozu and K. Nakamura, Rainrate and raindrop size distribution observations in
Darwin Australia, Proc. URSI-F Special Open Symp. Regional Factors in Predicting Radiowave
Attenuation due to Rain, Rio de Janeiro, Brazil, (1990)
Suitz,T., S. Uratsuka, A. Takahashi, O. Watanabe and F. Nishio, Development of a radar forcrevasse detection, IEICE, Japan, Proc. 1989 Int. Symp. Noise Clutter Reject. Radars Imaging
Sensors, Kyoto, Japan, 666-669 (1989)
Suitz, T. and S. Uratsuka, Remote sensing of antarctic ice by short distance high resolution
radars, J. Rem. Sens. Soc. Japan, 10, 106-111 (1990), (in Japanese)
Taga, T., Analysis for effective gain of mobile antennas in land mobile radio environments,
IEEE Trans. Veh. Technol., 39, 2, 117-131 (1990a)
Taga, T., A theoretical study of measurement of cross polarization power ratio (XPR) in mobile
communication environments, Trans. IEICE Japan, J73-B-II, 10, 536-545 (1990b)
Taga, T., Analysis for correlation characteristics of antenna diversity in land mobile radio
environments, Trans. IEICE Japan, J73-B-II, 12, 883-895 (1990c)
Takai, H. and T. Manabe, An indoor propagation analysis using delay profiles measured by thesuperresolution pulse-compression method, 1991 URSI North American Radio Science
Meeting, Ontario, Canada, p. 432 (1991).
Takamatsu, H., M. Kajii, T. Kozu, M. Kojima and K. Okamoto, Precipitation radar for TropicalRainfall Measuring Mission (TRMM), Proc. 43rd Congress of IAF, IAF-92-0097, Washington,
D. C., USA, (1992)
Takano, T. and S. Yonehara, Basic investigations on an angle measurement system using alaser, IEEE Trans. AES, 26, 4, 657-662 (1990)
Takano, T., Research on OSC and optical space technologies at ISAS, Proc. Int. Workshop
Optical Space Commun., 4.3.1-4.3.30 (1990)
Takano, T., Z. Yamamoto, E. Mizuno, M. Yamada, S. Oh-hashi, M. Tsuchiya, N. Kawashima,
H. Hirosawa and T. Hayashi, Receiving system for radio science experiment of Voyager-2
spacecraft Neptune occultation, Trans. IEICE Japan, J75-B-II, 1, 47-55 (1992), (in Japanese)
Tanaka, K., T. Ikegami and S. Ohmori, Evaluation of signal variation in land mobile satellite
communications, Proc. IEEE AP-S Int. Symp., Dallas, USA, 1808-1811 (1990)
Tanaka, T. and A. Akeyama, Modeling of propagation delay profile in urban areas surroundedby mountains, IEEE AP-S Digest Session-83, 1804-1806 (1990)
Tanaka, T., A. Akeyama and S. Kozono, Urban multipath propagation delay characteristics inmobile communications, Trans. IEICE Japan, J73-B-ll, 11, 772-778 (1990), (in Japanese)
Tanaka, T., S. Aoyama and S. Kozono, Effects of narrowing and tilting of base station antenna
beam in mobile radio delay spread reduction, Proc. 1992 Int. Symp. Antennas Propagat.
(ISAP'92), Sapporo, Japan, 385-388 (1992)
Thomas, H., T. Ohgane and M. Mizuno, A novel dual antenna measurement of the angular
distribution of received waves in the mobile radio environment as a function of position anddelay time, Proc. 42nd IEEE Veh. Technol. Conf., 546-549 (1992)

Tsuda, T., T. Adachi, Y. Masuda, S. Kato and S. Fukao, Temperature fluctuations in the
troposphere observed with the MU radar/RASS, Proc. Lower Tropospheric Profiling: Needs andTech., Boulder, USA, 87-88 (1991)
Umehara, T., Y. Ohno and T. Iguchi, HF ocean radar -- Signal processing for the HF ocean
radar, Rev. Comm. Res. Lab., 37, 3, 383-391 (1991a), (in Japanese)
Umehara, T., T. Iguchi and Y. Ohno, HF ocean radar -- Observation of current on the northwest
coast of Kume Island by the ocean radar, Rev. Comm. Res. Lab., 37, 3, 405--415 (1991b), (inJapanese)
Uratsuka, S., K. Okamoto, F. Nishio, M. Mineno and S. Mae, Sea ice thickness measurement
using step frequency radar, Proc. 1989 Int. Symp. Noise Clutter Rejection Radars Imaging
Sensors, Kyoto (Japan), 656-666 (1989)
Yamada, H., M. Ohmiya, Y. Ogawa, K. Itoh, Superresolution techniques for time-domain
measurements with a network analyzer, IEEE Trans. Antennas Propagat., 39, 2, 177-183 (1991)
Yamada, H., Y. Ogawa and K. Itoh, A time-domain superresolution technique for scattering
measurements, Proc. 1992 Int. Symp. Antennas Propagat. (ISAP'92), Sapporo, Japan, 10011004 (1992)
Yamada, M. and Y. Karasawa, Model testing for XPD on Earth-space paths, Proc. URSI 23rd
General Assembly, Prague, Czechoslovakia, 608 (1990)
Yamada, M., Y. Karasawa, H. Shimoi and M. Yokoyama, Compensation techniques for rain
depolarization in satellite communications, Proc. URSI 23rd General Assembly, Prague,
Czechoslovakia, 604 (1990)
Yamasaki, H., J. Awaka, A. Takahashi, K. Okamoto and T. Ihara, Measurements of soilbackscatter with a 60 GHz scatterometer, Proc. IGARSS'91, Espoo, Finland, 403-406 (1991)
Yamasaki, H., J. Awaka, A. Takahashi, K. Okamoto and T. Ihara, Measurement of soilbackscattering with a 60-GHz scatterometer, IEEE Trans. Geosci. Rem. Sens., 30, 761-766(1992)
Yasunaga, M., Y. Karasawa, T. Shiokawa and M. Yamada, Space and frequency correlation ofmultipath fading due to sea surface scattering and its reduction by diversity technique for low
G/T mobile satellite communications, Proc. 1989 Int. Symp. Noise Clutter Rejection in Radars
and Imaging Sensors , Kyoto, Japan, 42-47 (1989)
Yasunaga, M. and Y. Karasawa, A simple prediction method of multipath fading due to sea
surface reflection in mobile satellite communications, Trans. IEICE Japan, J73-B-II, 12, 876882 (1990), (in Japanese)
Yoshikawa, T., B. A. Thompson, M. Yoshikawa and J.M. Lomo, Line-of-sight microwave
radio propagation characteristics in Ghana, Proc. 1992 Int. Symp. Antennas Propagat.
(ISAP'92), Sapporo, Japan, 885-888 (1992)
Zhang, G. F., J. Hou, S. Ito and T. Oguchi, Optical wave propagation in random media
composed of both turbulence and particles: radiative transfer equation approach, J. Comm. Res.
Lab., 37, 151/152, 43-62 (1990)