bluuebunny/crossref_metadata_2025 huggingface dataset:
A low‐loss ring UWB bandpass filter
Authors: Weng Min‐Hang , Liu Shih‐Kun , Liu Yi‐Ting , Hung Cheng‐Yuan
Published: June 2008

In this article, a compact and low loss ring ultra‐wideband (UWB) bandpass filter (BPF) with an enlarged perturbation element is designed and implemented on FR4 substrate. This filter at center frequency f0 of 4.16 GHz has presented almost very good measured characteristics including the bandwidth of 3.04–5.27 GHz (3‐dB fractional bandwidth of 54%), a low insertion loss of 0.8 dB, a high passband selectivity due to two transmission zeros in the passband edges, and a low group delay varied between 0.1 and 0.6 ns. Experimental results of the fabricated filter show a good agreement with the predict results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2317–2319, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23639
Electrically long rectangular patch antenna fed by meandering probe with wideband and high gain characteristics
Authors: Lai Hau Wah , Luk Kwai Man
Published: June 2008

A linearly polarized electrically long rectangular patch antenna fed by a meandering probe is presented. By increasing the width of a patch antenna to 1.05λ0, the gain of the antenna can be increased. The antenna has an impedance bandwidth of 26% (SWR < 1.5), a gain of 11.2 dBi, and a crosspolarized level less than −15 dB across the operating bandwidth. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2289–2292, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23640
Comparison of wideband Gilbert micromixers using SiGe HBT and GaInP/GaAs HBT technologies
Authors: Syu Jin‐Siang , Meng Chinchun , Wu Chih‐Kai , Huang Guo‐Wei
Published: June 2008

Wideband downconversion mixers are demonstrated by using both 0.35‐μm SiGe heterojunction bipolar transistor (HBT) and 2‐μm GaInP/GaAs HBT technologies. A micromixer topology is implemented in the RF port while a differential type shunt–shunt feedback amplifier and a differential‐to‐single CE‐CC output buffer are used in the IF stage. The frequency response analysis and systematic measurement approach for a wideband Gilbert mixer are proposed in this article for each individual stage of local frequency (LO), radio frequency (RF), and intermediate frequency (IF). The differential LO signals are generated by several off‐chip 180° hybrids to cover more than 8:1 bandwidth. The SiGe HBT Micromixer achieves the conversion gain of 6 dB, IP1dBof −17.5 dBm, and IIP3of −7 dBm with the 3.3‐V supply voltage and the power consumption of 37.5 mW. On the other hand, the GaInP/GaAs HBT Micromixer achieves the conversion gain of 25 dB, IP1dBof −25 dBm, and IIP3of −15 dBm with the 5‐V supply voltage and the power consumption of 50 mW. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2254–2257, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23642
Size reduction of microwave and millimeter‐wave passive circuits by UC‐PBG in standard 0.18‐μm CMOS technology
Authors: Lin Shuiyang , Yang Liwu , Sun Xiaowei
Published: June 2008

Size reduction of microwave and millimeter‐wave (mm‐wave) passive circuits incorporating a defective uniplanar compact photonic bandgap (UC‐PBG) slow‐wave structure is investigated. Benefited from the multilayer mental technology of the standard 0.18‐μm CMOS process, thin film microstrip structure is properly constructed on the lossy silicon substrate to reduce substrate loss. Defected periodic patterns on the ground plane are used to contribute to an enhancement of the effective dielectric constant and the slow‐wave factor is 14% increased by the use of UC‐PBG ground. Microwave and mm‐wave passive circuits including resonator and filter are designed and fabricated. Measured results show that the use of UC‐PBG ground has induced a frequency drop of 14% and validate the size reduction concept by using UC‐PBG. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2251–2254, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23643
Simultaneous measurement of temperature and strain based on ARC‐induced long‐period fiber gratings. A case study
Authors: Rego G.
Published: June 2008

We present a potential sensor head for the simultaneous measurement of temperature and strain based on the concatenation of two long‐period fiber gratings arc‐induced in different fibers. Despite being the temperature and strain sensitivities of the individual gratings well defined, we demonstrate that the sensor cannot perform the simultaneous measurement of those physical parameters. This fact, results from the uncertainty in finding the determinant of the inverse matrix. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2472–2474, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23644
Post‐CMOS micromachined nickel tunable‐capacitors with a large tuning‐range under low actuating voltage
Authors: Gu Lei , Wu Zhengzheng , Li Xinxin
Published: June 2008

A novel metal micromachining technique is presented, with which both area‐tuning and gap‐tuning variable capacitors are designed and fabricated. Mainly comprising nickel electroplating and gaseous isotropic etching, the developed micromachining technique can be processed in low resistivity silicon substrate under low temperature (max. 120°C). Thus, the micromachined tunable‐capacitors can be on‐chip integrated into RF (radio‐frequency) ICs by means of post‐CMOS compatibly process. The fabricated tunable‐capacitors are measured, generally resulting in a larger tuning‐range than 200% (namely 3:1) under 4‐V actuation voltage. The Q‐factor for the area‐tuning capacitor (C0= 0.28 pF) is measured as 169 at 1 GHz and 46 at 2 GHz, respectively, while the gap‐tuning style capacitor (C0= 0.37 pF) is with the Q measured as 87 at 1 GHz and 35 at 2 GHz. With the successful application in the tunable‐capacitors, the developed post‐CMOS compatible metal micromachining techniques are promising for high‐performance on‐chip RF/microwave passives. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2469–2472, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23645
Integrating a dual‐band filter into the dual‐band VCO module to achieve harmonic suppression
Authors: Tang Ching‐Wen , Chu Wei‐Hsien
Published: June 2008

A dual‐band voltage‐controlled oscillator (VCO) module is proposed by integrating a novel dual‐band filter with a dual‐band VCO. The resonator designed with the LC‐tuned concept in the VCO is capable of switching between two frequency bands. Moreover, the dual‐band filter designed with multilayered structure is adopted to achieve harmonic suppression. As a result, the developed VCO module has the capability of harmonic suppression more than 38.61 dB for the measurement upon to two designed frequency bands. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2440–2442, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23647
Tunable coherent photonic microwave notch filter based on PSFBG with optical phase shifter
Authors: Keun Oh Choong , Hanawa Masanori , Kim Tae‐Young , Yun Chun Young , Park Chang‐Soo
Published: June 2008

A tunable coherent photonic microwave notch filter based on phase‐shifted fiber Bragg grating is proposed. Because of the Yb3+/Al3+ codoped optical fiber between two sub‐FBGs, the optical phase of the delayed signal is linearly and precisely controlled by adjusting the injected pump power at around 980 nm. By changing the optical phase shift inside the filter, notch frequency can be varied continuously keeping its free spectral range. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2409–2411, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23648
Miniaturized implantable broadband antenna for biotelemetry communication
Authors: Liu Wen‐Chung , Yeh Feng‐Ming , Ghavami Mohammad
Published: June 2008

A body‐implantable miniaturized and broadband stacked antenna suitable for biotelemetry communication is proposed. By properly arranging a rectangular three‐layer slotted patch structure, the designed antenna with only 10 × 10 × 1.9 mm3 can provide a −10 dB impedance bandwidth of 50 MHz in the 402–405 MHz medical‐implant‐communication‐service frequency band. When compared with the reported most compact antenna, the proposed design achieves not only a more monopole‐like radiation pattern with a double‐radiation efficiency of 0.61% but also a size reduction of 43%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2407–2409, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23649
An integrated 8‐mW 2.4‐GHz CMOS RF receiver for low‐power WPAN
Authors: Kwon Ickjin , Lee Minkyung
Published: June 2008

A fully integrated 2.4‐GHz CMOS receiver IC for the low‐power wireless personal area network (WPAN) is reported. In the proposed receiver, low power operation is achieved by using low voltage linear RF front‐end circuit based on current mirror amplifier based mixer and the interleaved analog baseband filter‐amplifier chain. The fully integrated receiver was fabricated in 0.18 μm CMOS technology and IIP3 of −29 dBm and noise figure of 9.6 dB at high gain mode were obtained at 8.4 mW power consumption from a 1.2 V supply. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2345–2348, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23652
Experimental demonstration of narrow beam monopole antenna embedded in low effective index of refraction (n < 1) wire medium
Authors: Zhou Rongguo , Zhang Hualiang , Xin Hao
Published: June 2008

A narrow beam monopole antenna is realized by embedding the antenna within a periodic metallic wire array. The 2D wire array is designed to have an effective index of refraction smaller than unity (neff < 1) at the X‐band frequencies (8–12 GHz), within which the antenna operates. The narrow beam effect due to the low refractive index of the wire medium is demonstrated in both simulation and experiment. Measured antenna properties including return loss and radiation pattern are in good agreement with simulation results. This simple and straightforward antenna design methodology can be applied at any microwave frequency. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2341–2345, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23653
Angle and polarization‐independent bandstop frequency selective surface for indoor wireless systems
Authors: Kiani Ghaffer I. , Esselle Karu P. , Ford Kenneth L. , Weily Andrew R. , Panagamuwa C.
Published: June 2008

A novel bandstop frequency selective surface (FSS) is presented. It has good frequency stability for horizontally, vertically, and circularly polarized waves, incident normally or at oblique angles. This bandstop characteristic can provide physical security to WLAN and other indoor wireless systems, whereas passing mobile/cellular phone and personal communication signals. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2315–2317, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23654
An UWB CMOS voltage‐controlled oscillator with 2–6 GHz tuning‐range using active inductor technology
Authors: Wei Chien‐Cheng , Chiu Hsien‐Chin , Yang Yi‐Tzu , Fu Jeffrey S. , Feng Wu‐Shiung
Published: June 2008

An ultra‐wideband voltage‐controlled oscillator (VCO) in a standard 0.18‐μm CMOS process is presented in this article. The designed VCO adopts two active inductors to replace the passive spiral inductors; this results in an increase in tuning‐range and chip area reduction. The active inductor provides a variable inductance range from 1.7 to 3.6 nH, so that the output frequencies of the novel VCO can be obtained from 2 to 6 GHz, with a tuning‐range of around 100%. According to the experimental result, it indicates that the proposed design exhibits a significant wide tuning‐range and compact chip size compared with a standard VCO with passive inductors. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2311–2315, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23655
Taking advantage of a dual‐gate FET resistive mixer for ASK remodulation in a phase conjugating antenna
Authors: Aballo T. , Cabria L. , García J. A. , Marante F. R.
Published: June 2008

In this letter, the use of a dual‐gate FET resistive mixer in a phase conjugating antenna is proposed. Applying a pulsed data signal to the second gate terminal, the amplitude of the time‐varying output conductance can be controlled. By means of an appropriate integration of the mixer with an aperture coupled patch, an amplitude shift keying modulation of the phase‐reversed signal is achieved. The capability of the proposed solution for retransmitting information back to the interrogation position is finally proved through measurements in a backscatter test setup. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2283–2287, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23656
Novel planar tapered‐slot‐fed UWB antenna
Authors: Yao Yuan , Chen Wenhua , Huang Bin , Feng Zhenghe
Published: June 2008

A planar tapered‐slot‐fed antenna is proposed in this article. The antenna is printed on a dielectric substrate. Measured and simulated results are used to demonstrate the performance of the antenna. It can be seen that this type of antenna is suitable for ultra‐wideband (UWB) applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2280–2283, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23657
Circularly polarized stacked antenna with a high‐impedance ground plane for RFID reader applications
Authors: Sun Jwo‐Shiun , Lee Yi‐Chieh
Published: June 2008

A circularly polarized (CP) stacked antenna for the long range reader of a RFID is studied. The proposed CP antenna using stacked patch technique with a high‐impedance ground plane exhibits fairly good performances of 30 MHz bandwidth for 3 dB axial ratio, 70 MHz bandwidth referred to 10 dB return loss at the center frequency of 915 MHz. The gain of the designed antenna is more than 7 dBi over 902–928 MHz and 922–928 MHz and the reading range of the reader reaches 5.5 m. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2248–2250, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23658
Six‐band internal antenna for small‐size mobile phone
Authors: Li Wei‐Yu , Wong Kin‐Lu
Published: June 2008

A promising six‐band internal antenna suitable for small‐size mobile phone application is presented. The mobile phone considered in this study has a system ground plane of length 60 mm only, much less than that of the general mobile phones. For such small‐size mobile phones, it is not easy for the embedded antenna to achieve a wide operating band at 900 MHz for GSM850/900 operation. The proposed antenna solved the problem with a reasonable occupied volume. The antenna mainly comprises three radiating elements of two longer monopoles and a shorter monopole, which are configured to occupy a volume of 3.6 cm3 only. The two longer monopoles incorporating an external parallel chip inductor lead to the successful excitation of a wide operating band for the antenna's lower band to cover GSM850/900 operation. Moreover, the three monopoles together contribute to the excitation of a very wide upper band to cover GSM1800/1900/UMTS/WLAN operation. That is, the antenna can perform six‐band operation for WWAN and WLAN communications. The proposed antenna is studied in detail in this article. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2242–2247, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23659
Performance analysis of parallel FDTD method on the different platforms
Authors: Yu Wenhua , Liu Yongjun , Yang Xiaoling , Mittra Raj , Lu Yongquan , Wang Pai , Che Qing , Lu Rui
Published: June 2008

In this communication, we investigate the performance of parallel FDTD code on a Gigabit Ethernet and optical network. It is fact that the optical network is necessary for a large cluster due to its wide bandwidth and small latency. However, for a small cluster, the Gigabit Ethernet will have a better ratio of performance to price. We also investigate the difference between high performance server and regular PC for the parallel FDTD code. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2465–2467, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23661
A multilayered triplexer with low‐temperature cofired ceramic technology
Authors: Tang Ching‐Wen , Hsu Huan‐Chang
Published: June 2008

A multilayered triplexer is proposed in this article. The ordered of this proposed triplexer can be reduced by inserting a transmission zero, which can also enhance the isolation between two separate passbands. Lowpass and highpass filters, which can make a diplexer due to their complementary characteristics, are utilized to reduce the insertion loss of the proposed triplexer. Moreover, the low‐temperature cofired ceramic technology can miniaturize the size of the triplexer. The procedures of circuit design are provided in this article as well. Excellent agreement between measurement and simulation validates the feasibility of the proposed configuration. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2399–2403, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23663
Broadband digital phase shifter based on composite right/left‐handed transmission line
Authors: An Jian , Wang Guang‐Ming , Zhang Chen‐Xin , Qu Shao‐Bo , Zhang Peng
Published: June 2008

The broadband digital phase shifters are valuable for the modern phase array antennas. Under balanced condition, composite right/left‐handed transmission line (CRLH TL) is broadband because of its unique hyperbolic‐linear dispersion relations. A broadband 4‐bit digital phase shifter based on the broadband property of CRLH TL is designed. When the absolute error is less than ±5°, for the 180° stage of the phase shifter, the relative bandwidth achieves 31.3%, while the conventional 180° switched line phase shifter only achieves 8.9%. And the unique hyperbolic‐linear dispersion relations are also able to minimize the area of the phase shifter. A simple circuit to test the right‐handed (RH) effect of the left‐handed (LH) TL is fabricated and used successfully in the design process of the 4‐bit digital phase shifter. The simulation and experiment results show that the design method of the phase shifter is feasible. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2365–2368, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23665
An integrated 24‐GHz differential VCO using SiGe HBT technology
Authors: Hamed Karim W. , Freundorfer Alois P. , Antar Yahia M. M.
Published: June 2008

This letter presents the design and performance characteristics of an integrated 24‐GHz differential voltage‐controlled oscillator (VCO). The developed VCO was implemented monolithically using the IBM BICMOS5HP process. Oscillator measured results show a tuning range of 1 GHz from 24.6 to 23.6 GHz with less than 1 dB variation in the differential output power over the entire tuning range. The fabricated VCO also exhibits a measured phase noise of −105 dBc/Hz at 1 MHz off the carrier. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2322–2325, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23666
Accurate integration of segmented 3D profile measurements using digital 2D fringe projection
Authors: Su Wei‐Hung , Hsu Yi‐Ling , Yu Kun‐Chang , Liu Hongyu
Published: June 2008

An improved integration approach for segmented 3D shapes using projected digitalized 2D pattern is presented. The digital 2D patterns are fabricated based on lithography techniques. Geometrical accuracy better than 0.5 μm can be achieved. Contrast ratio of the fringe pattern can be precisely controlled as well. With this pattern, integrated accuracy better than one part in one hundredth of the pixel size can be achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2474–2480, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23667
Double‐printed rectangular patch dipole antenna for UWB applications
Authors: Gao Guo‐Ping , Yang Xue‐Xia , Zhang Jin‐Sheng , Xiao Jin‐Xiang , Wang Fa‐Jia
Published: June 2008

A novel double‐printed rectangular patch dipole antenna suitable for UWB application is presented and investigated in this article. The effects of some important antenna parameters on the return loss of the proposed antenna have been investigated. Printed on the dielectric substrate and fed by a microstrip line, the antenna has been demonstrated to provide an UWB with return loss less than −10 dB from 3.1 to 10.6 GHz and the satisfactory radiation properties. A gain variation from 4.78 to 7.89 dB is obtained. The transfer function has flat magnitude and linear phase with smooth group delay being gained, which is advantageous to the transmission of the UWB signals. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2450–2452, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23668
Simple adaptive first‐order PMD compensator using a Faraday rotator and a variable DGD element
Authors: Pan Shilong , Wang Jiajun , Lou Caiyun , Yang Yanfu , Dai Wuju
Published: June 2008

A two‐degree‐of‐freedom (DOF) polarization mode dispersion (PMD) compensator has been developed to cancel the effects of first‐order PMD. The compensator comprises of a Faraday rotator (FR) and a dynamically varying crystal differential‐group‐delay (DGD) element. Because of the reduced number of control parameters, the compensator potentially possesses the desirable features of simple control, fast response, and cost saving. Principle of operation is validated by theoretical analysis and successful automatic PMD compensation is achieved in a 40 Gbit/s nonreturn‐to‐zero (NRZ) system. The compensator increased the average DGD allowed from less than 23% per bit‐slot for the uncompensated case to 42% at an outage probability of 10−4. Fast response of the compensator is also observed. The optimum setting of the compensator can be found in about 10 nregulating steps for all PMD emulator (PMDE) setting. These features allow the effective mitigation of the first‐order PMD effects within an optical fiber channel. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2417–2420, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23669
Cad of stacked patch antennas through multipurpose admittance matrices from FEM and neural networks
Authors: Córcoles Juan , González Miguel A. , Zapata Juan
Published: June 2008

In this work, a novel computer‐aided design methodology for probe‐fed, cavity‐backed, stacked microstrip patch antennas is proposed. The methodology incorporates the rigor of a numerical technique, such as finite element methods, which, in turn, makes use of a newly developed procedure (multipurpose admittance matrices) to carry out a full‐wave analysis in a given structure in spite of certain physical shapes and dimensions not yet being established. With the aid of this technique, we form a training set for a neural network, whose output is the desired response of the antenna according to the value of design parameters. Last, taking advantage of this neural network, we perform a global optimization through a genetic algorithm or simulated annealing to obtain a final design. The proposed methodology is validated through a real design whose numerical results are compared with measurements with good agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2411–2416, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23670
Lumped element equivalent circuit for the cymbal resonator bandpass filter
Authors: Kelly James R. , Seager Rob D. , Wong Thomas
Published: June 2008

This article presents an equivalent circuit for the microstrip cymbal bandpass filter (Strassner and Chang, Microwave Opt Technol Lett 28 (2001), 33–34; Strassner and Chang, IEEE Trans Microwave Theory Techn 50 (2002), 1431–1432), together with an ABCD matrix. The circuit models the frequency response of the filter accurately. A set of polynomial equations were also developed as a design aid. These equations give the equivalent circuit component values. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2381–2384, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23671
A novel implementation of composite right/left‐handed transmission line
Authors: Ma Jia‐Jun , Cao Xiang‐Yu , Liu Tao
Published: June 2008

A novel composite right/left‐handed transmission line is presented in this letter. The proposed CRLH structure can be considered as a CPW version composed with a pair of parallel spiral interdigital and a conjunctive stub. The spiral interdigital enlarges the series capacitance, and the adjustable conjunctive stub increases the shunt inductance. So, this structure is simpler and more compact compared with the conventional one. Its left‐handed material property is confirmed by simulation and measurement results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2379–2381, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23672
Resonant frequency of asymmetrically loaded annular microstrip antenna
Authors: Mahajan Madhurika , Khah Sunil Kumar , Chakarvarty T. , De A.
Published: June 2008

Theory of resonant frequency of an annular ring antenna with asymmetric multiple shorting posts is presented using modified Cavity Model. The posts are thin in diameter with respect to the diameter of ring. For accurate formulation, the shorting posts have been considered as inductive impedances at the frequency of interest. It is shown that for asymmetric loaded ring, TM11 is the dominant mode. The simple tool presented can be suitably modified to incorporate switching diodes or varactor diodes. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2351–2353, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23673
Reconfigurable patch antenna with switchable L‐shaped slots for circular polarization diversity
Authors: Raghavan S. , Shanmuganantham T. , Kishore Kumar M. S.
Published: June 2008

A novel design of a microstrip patch antenna incorporated by two orthogonal L‐shaped switchable slots is proposed to achieve circular polarization. Two pin diodes are inserted into these L‐shaped slots and by making these two pin diodes ON and OFF the antenna can radiate with either right handed circular polarization or left handed circular polarization with wide bandwidth. This antenna can be used in unlicensed & licensed WiMAX (IEEE802.16a), future planetary missions and satellite link. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2348–2350, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23674
A miniaturized parallel‐coupled microstrip filter using over‐coupled end stages with symmetrical tapped‐line structure
Authors: Lin Kun‐Ying , Liao Shry‐Sann
Published: June 2008

In this article, a miniaturized parallel‐coupled microstrip filter is presented. The miniaturized design saves 80% circuit dimension compared to the conventional parallel‐coupled over‐coupled end stages filter with the symmetrical tapped‐line structure. Several design methods and miniaturization techniques were involved in this study to achieve 5f0 stopband suppression, including symmetrical tapped‐line, stepped‐impedance structure, bended and folded of transmission lines, and the coupling effect of microstrip‐lines. Also the asymmetrical tapped‐line structure is fabricated to achieve 6f0 stopband suppression. Good agreements between the simulated and measured results were also observed in all above cases. Furthermore, no lumped elements, via‐holes, and bonding wires are necessary for this miniaturized coupler, making it very useful for the modern wireless communication systems. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2271–2274, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23675
Left‐handed lumped transmission lines and left‐handed small impedance transformers
Authors: Hee‐Ran Ahn , Bumman Kim
Published: June 2008

Based on the concept that a left‐handed transmission line section has a negative electrical length, two Π‐type lumped equivalent circuits are presented, and it is newly suggested that a low‐pass filter type can be its lumped‐equivalent circuit under a certain condition. Applying the negative electrical length concept to Smith chart, left‐handed small impedance transformers are derived and two are validated by measurements, adding 180° right‐handed transmission lines to the impedance transformers. The measured results are in good agreements with predictions, showing that insertion and return losses are −0.23 and −22.5 dB, respectively. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2269–2271, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23676
GSM open‐loop duplexer filter with internal stubs
Authors: Bezerra A. L. , de Souza M. F. A. , e Silva F. R. L. , de Oliveira B. G. M. , de Melo M. T.
Published: June 2008

A duplexer filter with open‐loop resonators, having internal stubs, for the GSM band in the DSC1800 Cellular Radio Base Station standard is presented. The filters use square open‐loop resonators. Insertion of the stubs allows the perimeter of the loop to be less than λ/2, which is the length used in the canonical loop. The device was fabricated on PTFE (RO3010) board. An eight‐pole selective filter with a single pair of attenuation poles was used. A full‐wave EM simulator was used to obtain the dimensions of the resonators. The measurement results are presented in comparison with the expected simulated values. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2422–2426, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23677
A high‐efficiency inverse class‐F power amplifier using GaN HEMT
Authors: Kim Hyoungjong , Choi Gilwong , Choi Jinjoo
Published: June 2008

The design and fabrication of a high‐efficiency inverse class‐F power amplifier using a 10‐W gallium nitride (GaN) high‐electron mobility transistor at 1 GHz is presented. The output load network has been used to control harmonic components for high‐efficiency operation. The measurement results show that power‐added efficiency of 74.2%, drain efficiency of 77.5%, and gain of 13.7 dB at an output power of 39.8 dBm for a continuous wave signal. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2420–2422, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23678
High‐finesse microlens optical fiber Fabry‐Perot filters
Authors: Jiang Yi , Tang Caijie
Published: June 2008

A novel optical fiber Fabry‐Perot filter (FFPF) based on two microlenses is proposed and demonstrated. The microlens is produced by forming a droplet with UV‐curing adhesive on the mirror of the filter. An FFPF with a finesse of 65 was obtained in the experiment. The advantages of the high‐finesse FFPF are the low cost and ease of construction. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2386–2389, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23679
Compact microstrip bandpass filter using two‐layer aperture‐coupled resonator‐embedded structure
Authors: Wang Yunxiu , Wang Bing‐Zhong , Wang Jianpeng , Xiao Shaoqiu
Published: June 2008

A two‐layer microstrip bandpass filter using aperture‐coupled topology is proposed in this article. The filter is composed of two uniform impedance resonators and two stepped impedance resonators located on two stacked microstrip layers, and the couplings between the resonators on the upper layer and those on the lower one are obtained by using three coupling apertures etched on a common ground plane placed between the two layers. With this two‐layer configuration, the proposed filter becomes very compact. To demonstrate the design, a four‐order bandpass filter is designed at 2.33 GHz. Compared with a single layer structure filter, a significant size reduction of about 50% is obtained. Furthermore, a stop‐band is extended to 8 GHz (3.43 f0) with a rejection better than −20 dB. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2357–2360, 2008; Published online in Wiley InerScience (www.interscience.wiley.com). DOI 10.1002/mop.23680
An alternate set of basis functions for the electromagnetic solution of arbitrarily shaped, three‐dimensional, closed, conducting bodies using method of moments
Authors: Mackenzie Anne I. , Baginski Michael E. , Rao Sadasiva M.
Published: June 2008

In this work, we present an alternate set of basis functions, each defined over a pair of planar triangular patches, for the method of moments solution of electromagnetic scattering and radiation problems associated with arbitrarily shaped, closed, conducting surfaces. The present basis functions are point‐wise orthogonal to the pulse basis functions previously defined. The prime motivation to develop the present set of basis functions is to utilize them for the electromagnetic solution of dielectric bodies using a surface integral equation formulation which involves both electric and magnetic currents. However, in the present work, only the conducting body solution is presented and compared with other data. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2354–2357, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23681
Improved technique used in high performance balanced vector modulators design
Authors: Hou Yang , Li Lingyun , Sun Xiaowei
Published: June 2008

This article describes and analyses an improved technique for the realization of balanced vector modulators. The analysis focuses on the effect of the Lange coupler characteristic impedance and the pHEMT total gate width on the modulator minimum insertion loss. A method of adjusting these parameters to optimum values is used to reduce the loss and achieve a more symmetrical constellation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2325–2328, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23682
A differential HBT power cell and its model
Authors: Lee Dong Ho , Chen Yue , Lee Kyung‐Ai , Hong Songcheol
Published: June 2008

A differential heterojunction bipolar transistor (HBT) power cell has been designed and modeled with additional model extraction patterns. The differential power cell, which is composed of a unit differential amplifier with a common emitter ballast resistor, has no gain degradation by the ballast resistors and has been implemented in InGaP/GaAs HBT technology. DC and AC characteristics are extracted from a half circuit of the differential power cell and thermal characteristics are extracted from a common‐mode circuit of that. Using the extracted model, a 5‐GHz differential power amplifier has been designed and fabricated with on‐chip output networks. The 5‐GHz differential power amplifier delivers 26 dBm ofP1dBwith 30% collector efficiency. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2262–2268, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23684
Design a PIFA with fold‐type ground plane for dual frequency mobile phone
Authors: Jiang Bo‐Tao , Mao Jun‐Fa , Jiang Liang
Published: June 2008

This article discusses results from a comprehensive investigation into the performance of two ground planes with various angle and ratio. Results from numerical simulations and measurements on prototype hardware are presented to show the influence of angle and ratio on resonant frequency, bandwidth, return loss of centre frequency, gain, and radiation patterns. A fold‐type mobile phone was designed, and TRP and TIS of it satisfy the CTIA certification. Present data are very useful in the design of a fold‐type mobile phone. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2258–2262, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23685
On‐chip dipoles in CMOS for wireless interconnect application
Authors: Jiang Liang , Yin Wen‐Yan , Mao Junfa
Published: June 2008

Two new on‐chip dipoles in standard 0.18‐μm CMOS are presented. The dipoles show higher inter‐chip transmission gain than traditional on‐chip meander dipole and smaller coverage than traditional on‐chip linear dipole. Comparison between the simulated and measured S11 of the on‐chip dipoles indicates that the existence of metal, poly and diffusion dummies decrease the resonances. Transmission gains with different inter‐chip distances and under different experiment conditions are calculated from measured S parameters, respectively. The design is helpful for the performance improvement of on‐chip dipoles and the farther CMOS integration of on‐chip antennas for wireless interconnect applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2446–2449, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23686
Low‐cost low‐sidelobe microstrip array with circular polarization
Authors: Tang Xiao‐Rong , Zhong Shun‐Shi , Sun Zhu , Liu Jian‐Jun
Published: June 2008

A low‐cost low‐sidelobe microstrip array antenna with a symmetric main beam of circular polarization (CP) is introduced. The array antenna has a coplanar feed network to excite a Chebyshev current distribution in the horizontal direction and a uniform distribution in the vertical direction of a 4 × 3 elements array. The CP operation is realized by using the corner‐fed quasi‐square patch elements. Measured results show that the array has a sidelobe level (SLL) of −21 dB in the horizontal plane, the half‐power beamwidth of 27° for two main planes both and the axial ratio of below 3 dB within the main beam. Its return loss is less than −10dB for the impedance bandwidth of 40 MHz. Its measured gain reaches 13.9 dB at 2.55 GHz. It is a low‐cost low‐sidelobe design with thin profile, simple structure, CP operation, and symmetric main beam, suited for the radio frequency identification (RFID) readers and other wireless systems. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2384–2386, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23687
A novel HTS filter with improved out‐of‐band rejection by introducing a quarter‐wavelength spiral stub
Authors: Piao Yunlong , Zhang Xiaoping , Guo Xubo , Jin Shichao , Cao Bisong , Peng Huili , Lu Xinxiang , Gao Baoxin
Published: June 2008

A novel high temperature superconducting (HTS) filter with split‐end stepped impedance resonators (SIR) is developed on MgO substrate. Spiral feedlines are used to meet the requirement of the external quality factor. A quarter‐wavelength (λ/4) spiral stub is introduced at the input feedline to provide additional transmission zeros at the high frequency end, which can improve both the out‐of‐band rejection and band‐edge steepness. The measured results at 70 K are in good agreement with the simulated ones. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2455–2457, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23688
Spherical representation of omnipotent Smith chart
Authors: Wu Yongle , Huang Haiyu , Liu Yuanan , Gao Zehua
Published: June 2008

In this article, A spherical representation of omnipotent Smith chart (OSC) for lossy nonreciprocal transmission lines (LNTLs) is presented. Such representation is an extension of OSC to deeply understand the general transmission lines with not only positive parameters but also negative ones. The spherical OSC has great potential in the application of RF systems which involve active devices. The mathematical expressions and the three‐dimensional (3D) graphics of the representation are showed in detail. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2452–2455, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23689
Low‐profile platform‐tolerant RFID tag with artificial magnetic conductor (AMC)
Authors: Kim Dongho , Yeo Junho , Ick Choi Jae
Published: June 2008

A novel low‐profile (≈0.01λ) platform‐tolerant passive RFID tag incorporated with artificial magnetic conductor (AMC) is proposed in this letter. It consists of a modified dipole antenna combined with an AMC ground plane and a tag chip attached on the feeding point of the antenna. The proposed tag shows long and stable read range from 4 to 6 m with a realized gain ranging from 4.1 to 5.3 dB for different platform materials such as metals and lossy liquids. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2292–2294, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23690
Compact triple‐band bandpass filter using pseudointerdigital trisection stepped impedance resonators
Authors: Chen Fu‐Chang , Chu Qing‐Xin
Published: June 2008

This letter presents a compact triple‐band bandpass filter using pseudointerdigital trisection stepped impedance resonators (SIR). By tuning the impedance ratio and physical length of trisection SIRs, the BPF has good triple‐band performances at 1.57‐/2.45‐/5.25‐GHz and high isolation among the three passbands. It is shown that the triple‐band bandpass filter has a small size in comparison of previous works. Good agreement is shown between the simulated and measured results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2462–2465, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23691
A novel microstrip low‐pass filter design method using square‐shaped defected ground structure
Authors: Vágner Petr , Kasal Miroslav
Published: June 2008

This article deals with novel microstrip low‐pass filter (LPF) design method using defected ground structure (DGS). The DGS allows significant length reduction of inductive microstrip lines, thus overall filter dimensions are reduced. Chebyshev prototype filter design is described and conversion from lumped network structure to microstrip structure with DGS resonators is shown. For given passband ripple and cutoff frequency, a 7th order filter design is described. S‐parameters of proposed LPF are simulated and theoretical results are compared with measurement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2458–2462, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23692
A CMOS opto‐electronic single chip using the hybrid scheme for optical receivers
Authors: Huang Jian‐Ming , Wang Chua‐Chin , Chiu Yi‐Jen
Published: June 2008

An opto‐electronic integrated circuit based on the hybrid scheme for an optical receiver front‐end is presented in this article. The proposed integrated circuit adopts the CMOS technology as the vehicle to integrate the InP‐based waveguide photodetector into the transimpedance amplifier (TIA) circuit. A regulated cascade structure is used to reduce the input impedance of the TIA. Hence, the proposed integrated circuit can achieve a very high bandwidth provided that the parasitic capacitance of the photodetector is up to 1 pF. The 3‐dB bandwidth and the transimpedance gain of the proposed circuit are 1 GHz and 64.5 dBΩ, respectively. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2430–2434, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23693
Experimental studies on microwave ablation in vitro animal tissues with microwave percutaneous coagulator
Authors: Che Wenquan , Chang Yumei , Yang Lisheng , Yang Lijiang , Chen Guoqiang
Published: June 2008

The principle and geometry of the microwave percutaneous coagulator system are investigated in this article; the main parts of the system are briefly introduced. A large number of experiments on porcine liver are carried out, and the temperature distribution within the liver are measured and illustrated, for cases of different injected microwave power and ablation time. In addition, the ablation areas in cases of different input microwave powers are also measured. All these results indicate the potential validity of this system on medical treatment of liver cancer of human body. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2426–2430, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23694
SOA‐based polarity‐preserving all‐optical wavelength conversion at 80Gbit/s: Wide conversion range, well dynamic characteristics and polarization insensitive
Authors: Yan Shuangyi , Zhang Jian‐Guo , Zhao Wei
Published: June 2008

This letter presents the effective design of a tunable 80 Gbit/s wavelength converter with a simple configuration consisting of a single semiconductor optical amplifier (SOA) and an optical bandpass filter (OBPF). Based on both cross‐gain and cross‐phase modulation in SOA, the polarity‐preserved, ultrafast wavelength conversion is achieved by appropriately filtering the blue‐chirped spectral component of a probe light. Moreover, the experiments are carried out to investigate into the wavelength tunability and the maximum tuning range of the designed wavelength converter. Our results show that a wide wavelength conversion range of nearly 35 nm is achieved with 21‐nm downconversion and 14‐nm upconversion, which is substantially limited by the operation wavelength ranges of a tunable OBPF and a tunable continuous‐wave laser in our experiment. We also exploited the dynamics characteristics of the wavelength converter with variable input powers and different injection current of SOA. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2392–2399, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23695
Balanced circulator structure with enhanced isolation characteristics
Authors: Lim Won‐Gyu , Yu Jong‐Won
Published: June 2008

In this article, we proposed a new balanced circulator structure having enhanced isolation characteristics between transmitter and receiver. Also, we show that the balanced circulator structure has little performance degradation for the varying load impedance. The balanced circulator consists of two branch‐line couplers and two circulators. The validity of the balanced circulator is confirmed by comparisons with the simulated and measured results obtained from the single circulator. The fabricated balanced circulator has about 50 dB isolation for the matched load impedance and above 30 dB isolation for the mismatched load impedance at 910 MHz, the center frequency of UHF RFID. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2389–2391, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23696
A 2‐mW low‐power 0.13‐μm CMOS VCO and LO generator for GPS applications
Authors: Kim Young‐Jin , Beak Dong‐Hyun
Published: June 2008

A low‐power GPS local generator using a 0.13‐μm CMOS process is presented. The complementary CMOS VCO, whose power consumption is about 0.6 mW, achieves the wide tuning range of 700 MHz and phase noise of −116 to −120 dBc/Hz at 1‐MHz frequency offset. To lower VCO gain and increase tunable control voltage range, aKVCOlinearizer is introduced by adopting multiple reference bias configurations. Using low‐power inverting amplifier, the power of local generator is minimized to below 2 mW in spite of providing 800 mVppswing voltage to passive mixer from 1.2 V supply. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2362–2365, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23697