Rainee N. Simons and Edwin G. Wintucky

Glenn Research Center, Cleveland, Ohio

Q-Band (37 to 41 GHz) Satellite Beacon

Architecture for RF Propagation Experiments

NASA/TM—2014-218124

April 2014
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Rainee N. Simons and Edwin G. Wintucky

Glenn Research Center, Cleveland, Ohio

Q-Band (37 to 41 GHz) Satellite Beacon

Architecture for RF Propagation Experiments

NASA/TM—2014-218124

April 2014

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Prepared for the

International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting

sponsored by the Institute of Electrical and Electronics Engineers

Chicago, Illinois, July 8–14, 2012
Acknowledgments

The authors would like to thank Hans-Henrik Viskum of TICRA, Copenhagen, Denmark, for the support that they received in 

the application of GRASP 9 Software Package to analyze an offset fed cut parabolic refl ector antenna discussed in this paper.

Available from

NASA Center for Aerospace Information

7115 Standard Drive

Hanover, MD 21076–1320

National Technical Information Service

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Available electronically at http://www.sti.nasa.gov

Level of Review: This material has been technically reviewed by technical management. 

This report contains preliminary fi ndings, 

subject to revision as analysis proceeds.
NASA/TM—2014-218124 1 

Q-Band (37 to 41 GHz) Satellite Beacon Architecture 

for RF Propagation Experiments 

Rainee N. Simons and Edwin G. Wintucky 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Abstract 

In this paper, the design of a beacon transmitter that will be 

flown as a hosted payload on a geostationary satellite to 

enable propagation experiments at Q-band (37 to 41 GHz) 

frequencies is presented. The beacon uses a phased locked 

loop stabilized dielectric resonator oscillator and a solid-state 

power amplifier to achieve the desired output power. The 

satellite beacon antenna is configured as an offset-fed cutparaboloidal reflector. 

1.0 Introduction 

A user community of ever-increasing size is consuming the 

available 25.5 to 27.0 GHz bandwidth allocations for Earth 

Exploration Satellite Service (EESS) downlink data 

transmission. In addition, high usage of the adjacent 27.5 to 

30.0 GHz Broadband Satellite System (BSS) uplink allocation 

has resulted in unintentional interference in the EESS band. It 

is inevitable that additional frequency will be needed in the 

near future. The next available and unused EESS allocation is 

the 37 to 41 GHz frequency band (Q-band). Before deploying 

a fully operational Q-band system in space, it is imperative to 

undertake a rigorous study on the attenuation, fading, 

scintillation, and polarization effects of rainfall on the Q-band 

signals in space-to-Earth links. 

The advantages of satellite communications at Q-band over 

the conventional Ka-band for data transmission includes 

reduced component sizes. In addition, the allocated bandwidth 

at Q-band is in excess of 4 GHz, which can enhance data 

transmission capacity by 10X or higher over current Ka-band 

systems. Furthermore, for a given antenna aperture dimension, 

the beamwidth is narrower and hence the spot size on Earth of 

a Q-band multibeam system is smaller, which enables greater 

spectral efficiency through frequency reuse. 

In the past, NASA Glenn Research Center pioneered the 

development of Ka-band communications by deploying the 

Advanced Communications Technology Satellite (ACTS) 

(Refs. 1 and 2). The ACTS served as a test bed in space for 

several of the new technologies needed for an operational Kaband system. In addition, the ACTS propagation experiments 

were instituted to investigate the effect of Earth’s atmosphere 

on the propagation of Ka-band satellite signals (Ref. 1). 

In this paper, we outline the design of a beacon transmitter 

that will be flown as a hosted payload on a geostationary 

satellite to enable propagation studies at Q-band frequencies. 

2.0 Satellite Beacon Architecture 

2.1 Q-band Beacon Transmitter 

The Q-band satellite beacon transmitter block diagram is 

presented in Figure 1. The generation of the unmodulated RF 

carrier at 39.0 GHz takes place in the phase locked loop (PLL) 

stabilized dielectric resonator oscillator (DRO), which derives 

its input reference from a highly stable temperature 

compensated crystal oscillator (TCXO). A chain of monolithic 

microwave integrated circuit (MMIC) based amplifiers 

consisting of a pre amp, driver amp and a balanced power amp 

(PA) boost the output of the DRO to the desired power level. 

The output of the PA is coupled via a coax-to-waveguide 

transition and a circulator to the antenna. Typical beacon 

specifications are listed in Table I. 

2.2 Satellite Beacon Antenna 

The satellite beacon antenna provides coverage to the 48 

contiguous states of the United States, which is also known as 

the CONUS, and will be located on the Earth deck of the 

spacecraft as illustrated in Figure 2. When viewed from a 

geostationary Earth orbit (GEO), at a longitude of around 

100 W, the CONUS subtends an angle of about 6 in the 

latitude plane (West-East) and 3 in the longitudinal plane 

(North-South) (Ref. 3) as illustrated in Figure 3. An aperture 

antenna for producing a single beam with 3-dB beamwidths of 

6 by 3 has dimensions approximately 13 by 26, where 

is the free space wavelength at the operating frequency 

(Ref. 3). This translates to approximately 100 by 200 mm at 

39 GHz. The on-axis gain of this antenna is about 32 dB 

assuming an aperture efficiency of about 40 percent. The gain 

of the satellite beacon antenna in the direction of a beacon 

receiver located at the edge of the coverage zone will be 3 dB 

lower, or 29 dB. To maximize heritage and minimize risk, the 

satellite beacon antenna is configured as an offset-fed cutparaboloidal reflector analogous to the ACTS system (Ref. 1). 

The reflector edge is contoured to produce a quasi-elliptical 

shape, which helps to suppress minor lobes (Ref. 4). The 

quasi-elliptical reflector and the offset conical horn feed 

assembly are schematically illustrated in Figure 4. The offset 

cut parabolic reflector and feed configuration are modeled 

using GRASP 9 software package from TICRA (Ref. 5). The 

antenna system geometry from two view angles is illustrated 

in Figures 5(a) and (b). The computed radiation pattern in the 
NASA/TM—2014-218124 2 

TABLE I.—BEACON SPECIFICATIONS 

Parameter Specifications 

CW carrier frequency 39 GHz 

Output RF power 1.5 to 2.0 W 

(end of life) 

Output RF power variation with 

temperature 

0.2 dB 

Output waveguide WR-22 

TCXO & PLLDRO phase stability 5 ppm (alternatively 

reference acquired 

from spacecraft) 

RF power detector output Yes 

Harmonics and spurs –40 dBc 

Phase noise –130 dBc/Hz at 

10 KHz 

OUTPUT VSWR 1.5:1 with reference 

to 50 

ON/OFF command and pulse duration Yes, 20 msec 

Bus voltage 287 V unregulated or 

50 V regulated 

Orbit GEO 

Mission life 3 to 4 years 

Isolator or circulator at output Yes 

y-z plane, Φ = 90° at 39 GHz is presented in Figure 6. The 

3-dB beam width is 3.9°. The cross-pol level is below 

20.0 dB. The computed radiation pattern in the x-z plane, 

Φ = 0° at 39 GHz is presented in Figure 7. The 3-dB beam 

width is 5°. The side lobes are asymmetric because of the 

offset geometry and are below 23 dB. The notional far-field 

contoured radiation pattern of this antenna is illustrated in 

Figure 8. The gain of the satellite beacon antenna in the 

direction of a beacon receiver at the edge of the coverage zone 

will be 3 dB lower, or 29 dB. 
NASA/TM—2014-218124 3 
NASA/TM—2014-218124 4 

2.3 Earth Station Antenna and Receiver 

The ground-receiving terminal will have a 1.2 m diameter 

reflector antenna with an offset feed. Table II provides the 

satellite beacon downlink budget in clear air, including the 

receiver noise characteristics, at the edge of the CONUS 

coverage. 

TABLE II.—Q-BAND GEO SATELLITE BEACON 

DOWN LINK BUDGET IN CLEAR AIR 

Q-band Satellite Beacon Transmitter Parameters 

Beacon saturated output power 

(end of life) 

2 W 

Satellite beacon antenna gain, on-axis 32 dB 

Signal Frequency and Polarization 

Unmodulated carrier signal frequency, 

linear 

39.0 GHz 

Q-band Earth Station Receiver Parameters 

Downlink signal frequency 39.0 GHz 

Antenna gain, on-axis, 39 GHz 51.6 dB 

Receiver IF bandwidth 10 KHz 

Receiving system noise temperature 396.9 K 

Downlink Power Budget 

Satellite beacon output power, 2 W (end 

of life) 

3.0 dBW 

Satellite beacon antenna gain, on-axis 32.0 dB 

Earth station antenna gain 51.6 dB 

Free space path loss at 39 GHz –215.3 dB 

Edge of beam loss for beacon antenna –3.0 dB 

Clear air atmospheric loss –0.8 dB 

Polarization loss –0.2 dB 

Earth station antenna pointing loss –0.5 dB 

Received power at Earth station –133.2 dBW 

Downlink Noise Power Budget in Clear Air 

Boltzmann’s constant –228.6 dBW/K/Hz 

System noise temperature, 396.9 K 26.0 dBK 

Noise bandwidth, 10 KHz 40.0 dBHz 

Receiver noise power –162.6 dBW 

Receiver noise power in one Hertz 

bandwidth 

–202.6 dBW per Hz 

C/N Ratio in Receiver in Clear Air 

C/N = –132.2 dBW – (–162.6 dBW) = 29.4 dB 

C/N in one Hertz bandwidth = 69.4 dB per Hz 

3.0 Conclusions 

The design of a beacon transmitter that will be flown as a 

hosted payload on a geostationary satellite to enable 

propagation experiments at Q-band frequencies (39 GHz) is 

described. In addition, the satellite beacon downlink budget in 

clear air at the edge of the CONUS coverage is presented. 

References 

1. R. Bauer, “Ka-band Propagation Measurements: An 

Opportunity with the Advanced Communications 

Technology Satellite (ACTS),” Proc. IEEE, vol. 85, no. 6, 

pp. 853–862, June 1997. 

2. R.J. Acosta, R. Bauer, R.J. Krawczyk, R.C. Reinhart, M.J. 

Zernic, F. Gargione, “Advanced Communications 

Technology Satellite (ACTS): Four-Year System 

Performance,” IEEE Jour. Selected Areas in 

Communications, vol. 17, no. 2, pp. 193-203, Feb. 1999. 

3. T. Pratt, C.W. Bostian and J.E. Allnutt, Satellite 

Communications, 2nd ed., John Wiley & Sons: New 

Jersey, 2003, pp. 117–118. 

4. H. Jasik, Ed, Antenna Engineering Handbook, 1st ed, 

McGraw-Hill: New York, 1961, Sections 12.2 & 25.3, pp. 

12–4 to 12–6 and 25–15 to 25–16. 

5. GRASP 9, General Reflector Antenna Software Package, 

TICRA, Copenhagen, Denmark. 

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Q-Band (37 to 41 GHz) Satellite Beacon Architecture for RF Propagation Experiments 

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Simons, Rainee, N.; Wintucky, Edwin, G. 

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14. ABSTRACT

In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation 

experiments at Q-band (37 to 41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator 

oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed 

cut-paraboloidal reflector. 

15. SUBJECT TERMS

Telecommunications; Transmitters; Deep space network; Space communication; Satellite communications; Microwave transmission; 

Microwave amplifiers; Power amplifiers 

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