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A “thru-short” noise de-embedding method for MOSFETs is presented. The capability of the “thru-short” method has been validated through a comparison of measured and de-embedded noise parameters using different methods. It is shown that the “thru-short” method is reliable for on-wafer de-embedding of both S-parameters and noise parameters up to 18 GHz. Noise contributions from the parasitics due to the contact pads and interconnections surrounding the MOSFET can be determined and removed accurately. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1379–1382, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24330

The performance of conventional common-collector Colpitts oscillators is limited at higher frequencies due to the parasitic base-collector capacitance Cbe and the base-emitter capacitance Cbe. Due to the Miller effect, the parasitic capacitance Cbe significantly reduces the negative resistance. A large collector inductor further reduces the negative resistance. This paper presents a solution based on parasitic cancellation to increase the negative resistance and improve the isolation between the RF output and the resonator. It is also shown that the technique allows designers to make a tradeoff between higher negative resistance and lower power consumption.

A wide-slot waveguide antenna implemented on low-temperature cofired ceramic technology is presented. The overall antenna is excited by aperture coupling. The design is simulated and validated by experimental measurement. The measured result shows that a 10-dB return loss has been achieved across the bandwidth from 2.6 GHz to 12.8 GHz, thus amounting to 132.5%. The measured radiation pattern of the proposed antenna is also presented and discussed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2181–2184, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23613

A novel tri-band electromagnetic bandgap (EBG) fed coplanar slot antenna is proposed and adopted for this investigation. With the integration of the EBG as an impedance matching element, a wider impedance bandwidth response is obtained for all the bands. Analytical expression for designing the coplanar EBG unit cells are derived for the first time. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 954–960, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22315

A novel ultra-wideband (UWB) stacked microstrip patch antenna suitable for UWB application is presented in this article. This compact and planar proposed antenna is found to have a very broad impedance bandwidth as compared to the conventional electromagnetic coupled antenna. The proposed antenna is able to achieve an impedance bandwidth of about 101.8% for VSWR less than 2, centred at around 7 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1659–1665, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22555

The adoption of flower rings coupled with inner split rings within an open-square-loop resonator for size miniaturization is first analyzed and designed. To demonstrate the proposed technique of loading, a novel dual-mode open-loop resonator operating at 2.5 GHz is next designed. The proposed technique of perturbation achieves a 48.4% loading factor for the resonators. The proposed resonator is 2.94% smaller in area as compared to the meander loop resonator, and 5.5% smaller in area as compared to the hairpin resonator. Harmonic suppression is also easily achieved through the integration of these circular rings.

A novel multi-frequency transformer is developed based on the dual frequency transformer technique. The transmission line analysis shows that for a return loss of −10 dB, the three-pole transformer can achieve 160% bandwidth when compared with 60% of the dual frequency transformer. For verification, a novel UWB LTCC multilayer transition from CPW to microstrip is developed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 329–332, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22142

A novel electromagnetic-bandgap (EBG) in-phase hybrid-ring equal power divider is described. Coupled with the closed-form analytical expressions for the EBG structure, a systematic technique of design is presented for the first time. Compared to the conventional hybrid-ring equal power divider, based on the 15-dB return-loss criteria, an increase in both the input and output impedance bandwidth of approximately 10% from a starting frequency of 2.5 GHz, and a phase error of 0.006/spl deg/ within the passband have been achieved for the proposed structure. The proposed in-phase hybrid-ring equal power divider, besides providing a much broader bandwidth and occupying a smaller estate area, also possesses good harmonic suppression characteristic.

A wideband pentagon-slot microstrip antenna with a semicircle probe feed is proposed. The broadband characteristic is achieved by cutting a pentagon slot at each corners of the patch. The proposed antenna is able to achieve an impedance bandwidth of 68.3% for a VSWR of less than 2. Experimental comparison with a similar-size retangular microstrip patch antenna has also been conducted in this paper. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 500–505, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21211

This paper presents a novel approach to alternate the electromagnetic properties of the electromagnetic band gap (EBG), where a ferrite defect is introduced, and in addition, a DC magnetic field is applied to alternate the EBG's electromagnetic property. Numerous devices are examined, including a coupler and a Y-branch filter. The numerical experiments demonstrate that the devices electromagnetic characteristics can be easily adjusted by varying the DC magnetic-field intensity. In this paper, the examinations are performed using the scattering-matrix method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 395–400, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20481

A broad-banding technique for in-phase equal power divider is described. Detailed comparisons between the proposed variants of power dividers and the conventional in-phase power divider are also performed. Based on the 15-dB input and output return losses criteria, it is noted that a maximum impedance bandwidth of 44.3% for an amplitude error of /spl plusmn/0.9 dB and a phase error of /spl plusmn/1.8/spl deg/ can be achieved, for the first time, for divider with length more than 3/spl lambda//2 ring impedance transformer. A systematic design technique that relaxes some of the conventional constraint in in-phase hybrid ring equal power divider design, is also described.

The conventional approach for modeling the dc I-V characteristics of a MESFET transistor usually adopts the hyperbolic tangent dependence on V/sub ds/. On the contrary, our new empirical model describes the device drain current as a polynomial of effective gate-source voltage V/sub eff/. The derived model is capable of accurately modelling the subthreshold effect and the device current-voltage behavior at different operating regions, in particular, the device operation around the pinchoff region. Measured and modeled results of a 0.5-/spl mu/m gatelength MESFET device are compared and good agreement has been obtained. Comparisons between the proposed model, Curtice model, Chalmers model, and Parker model are also made in this paper. In addition, a single-stage class-AB amplifier was built with a commercial high-power MESFET transistor to verify the new model.

A novel bow-tie slot antenna fed by CPW is investigated. It is designed to work on a thick substrate (h=62 mil) with a high dielectric constant (er=10.1). Two metal stubs are introduced at the center of the bow-tie slot antenna to control the impedance matching and the cross-polarization level. As a result, no balun network is required. A parametric study based on a numerical spectral domain is performed. A bandwidth of more than 40% is achieved, and the experimental results are presented. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 206–211, 2000.

An improved Chalmers large-signal model for a GaAs MESFET transistor is proposed. A commercially packaged high-power MESFET transistor (Fujitsu FLC103WG) is adopted for the extraction. Both hot and cold condition measurements and a pulsed I/V measurement are performed to derive the model. For the verification of the model, a simple single-stage class-AB amplifier is subsequently built. The simulation and measurement results of the intermodulation distortion of this amplifier agree excellently. ©2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 311–316, 2000.

A novel coaxial-fed E-shaped microstrip patch antenna is proposed in this paper. The proposed antenna is found to have a much broader impedance bandwidth as compared to the conventional U-slot antenna. An impedance bandwidth of about 33.8% is achieved for the proposed E-plane antenna. Through the use of a washer on the proposed antenna, the probe inductor is compensated, and an impedance bandwidth of 40% is thus obtained. The E-plane radiation pattern for both the proposed antenna and the one incorporated with the washer remains relatively constant through the band. A comparison between the U-slot antenna and our proposed antennas is made in the paper. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 348–352, 2000.

A new electromagnetic bandgap (EBG) spatial power combiner is proposed. The prototype consists of the design of the EBG ground holes structure, the active-EBG coupler, and the Vivaldi antenna array. A 17 dB system gain coupled with a 5.5 GHz of impedance bandwidth and good out-of-band suppression has been achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1534–1536, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23421

A novel hybrid antenna structure that combines a rectangular dielectric resonator and a CPW-fed slot with tuning stub is proposed. The proposed antenna is designed to resonate at the lower (2.4 GHz) and upper (5.3 GHz) 802.11 WLAN frequency bands, respectively. Comparisons between the simulation and measurement results confirm the good properties exhibited by the proposed antenna. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 170–172, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21296

A novel multilayer broadband active-slot power divider is proposed for the first time. As compared to the conventional active multilayer power divider 7, whose 3-dB bandwidth of small-signal gain is typically about 40%, the overall 3-dB bandwidth of the small-signal gain of the proposed multilayer active-slot power divider is about 52%. Through the modification of the T-junction, the proposed power divider is able to provide the characteristics of balance, low loss, and broad band. The proposed device can also provide the possibility of uneven power outputs under appropriate load modifications and amplifications. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 10–12, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20029

A novel LTCC power combiner, which is adopted from conventional balun design, is presented. In contrast to the conventional balun network, our design provides one pair of nondifferential signals with minimum phase difference between the outputs. Experimental results are given in the paper to verify our theoretical analysis and design. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 255–257, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20269

In this paper, the characteristics of a bent meander-line probe fed patch antenna are investigated. The air-filled patches are designed at a height of about 9% of the wavelength and the bent meander-line probe fed antenna is able to achieve an impedance bandwidth of about 31% for a VSWR of less than 2. The four basswoods, which support the microstrip patch, are noticed experimentally to have little effect on the overall performance. The in-band return loss of the proposed antenna is found experimentally to be better than the recently proposed L-shaped probe patch antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 401–403, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10930

A new drain–gate avalanche current source model, which is controlled by Vds and Vgs, is proposed. A Fujitsu MESFET transistor, FLC-103WG, is adopted for measurement, and the model is extracted. Compared with several conventional models, the proposed model is found to be more accurate than the Curtice and Fujii model. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 269–271, 2000.

Conventional passive power dividers are narrowband and lossy. In this paper, we will introduce a new distributed power divider with active inductor termination. The numerical simulation results show that the proposed structure has a much wider bandwidth than the conventional active or passive power divider. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 177–179, 2001.

The design of millimeter-wave on-chip antenna has been plagued by the ground image current induced by the lossy substrate and the presence of ground plane below the chip. With the existence of this image current, it results in poor radiation property and impedance bandwidth. In this paper, a novel method that integrates the artificial magnetic conductor and a wideband slot antenna design is introduced. Two designs are implemented in mainstream CMOS technology. A gain of 2dBi at 60GHz and an impedance bandwidth of more than 126% have been obtained for the first time in standard CMOS.

In this paper, a compact dual-band hybrid DRA for WLAN is presented. In this antenna configuration, a vertical unsymmetrical T-junction strip adhered to the sidewall of the rectangular DR is utilized to excite radiating modes in the DR. A parasitic loop printed on the top of the DR is excited through the coupling to the feeding circuit. By connecting the parasitic loop and the DR in parallel, an 802.11 a/b dual-band hybrid DRA with compact size is proposed.

Modern aircraft are increasingly packed with advanced and often sensitive electronic systems, making them very vulnerable to electromagnetic interference. Furthermore, the growing communication arena adds rapidly into the environment high power transmitters that produce field strength in excess of a 100 V/m in the vicinity of aircraft flight paths, rendering particularly the high power HF a real hazard to the flying aircraft with dimensions being within the resonant band of HIT. This paper presents a quantitative approach to analyze this coupling mechanism. The feasibility of using NEC wire-grid scheme for analyzing field penetration into enclosures and interior cabling has been established for the first time. A full NEC wire-grid model of a fighter aircraft is developed and used extensively for simulation in support of theoretical predictions. Practical results and numerical insights, which are useful for aircraft engineers, are obtained directly on penetrating fields and cable coupling with different polarizationpsilas and frequencies both near and off resonance.

The magnetic shielding efficiency at 50 Hz of rooms with windows and doors is studied in this paper. The equation of the curl of magnetic vector potential is implemented through the finite element method to find the magnetic shielding efficiency. The entire analysis has been done in two dimensions. The shielding rooms with different sizes and windows openings are compared. The effects of thickness, conductivity, and permeability of the shielding materials are discussed. The effect of H field direction is also investigated. The shielding rooms made up of four different materials are compared and the edge effects due to ferromagnetic materials are discussed.

This paper describes a novel wideband CMOS differential four-quadrant analog multiplier which is part of a integrated correlator aiming for application in Ultra-Wideband (UWB) transceiver. By combining a conventional Gilbert cell and a gate-source injection multiplier with flipped voltage followers together, wide operation bandwidth is achieved with enhanced conversion gain. Simulation results show that the multiplier can provide a bandwidth of up to 9.2 GHz and a conversion gain of 19 dB. This multiplier is able to operate with a 0.2 ns narrow monocycle pulse. The proposed circuit has been designed and simulated using commercial 0.18-mum CMOS process and the power consumption is 10.8 mW under a 1.8 V DC voltage supply.

A ultra-wideband low noise amplifier (LNA) with integrated notch filter for interference rejection is designed using 0.18-mum CMOS technology. The three-stage LNA employs a current reuse structure to reduce the power consumption and a serial LC circuit with Q-enhancement circuit to produce band rejection in the 5-6 GHz frequency band. The load tank optimization for the current reuse stage is discussed for gain flatness tuning Measurements show that this LNA has a peak gain of 21.5 dB in the low band (3-5 GHz) and 15 dB in the high band (6-10 GHz) while consuming 12 mA of current from a 1.8 V DC supply. The measured noise figure (NF) and IIP3 are 4.0 dB and -18.5 dBm at 3.5 GHz, 5.1 dB and -15.5 dBm at 7.2 GHz respectively. A 6-12 dB gain notch in the 5-6 GHz is realized for interference rejection.

In this paper, a novel integrated hybrid antenna structure for system-in-package (SiP) application is presented. Part of the chip package is utilized as the hybrid dielectric resonator antenna (DRA). The hybrid DRA comprises a rectangular dielectric resonator (DR) and a conductor-backed coplanar waveguide (CB-CPW) slot. The CB-CPW slot is designed to simultaneously act as an effective radiator and the feeding structure of the DR. Dual resonances of the two radiators are merged to extend the antenna's bandwidth. A prototype antenna for 5 GHz WLAN achieved 20.4% input impedance bandwidth and around 6 dBi gain. The proposed configuration provides a possible solution to the antenna integration for SiP system.

The oscillation frequency of conventional common collector Colpitts oscillators is limited due to the parasitic base collector capacitance Cbc and base emitter capacitance Cbe. The Miller effect from the parasitic capacitance Cbc significantly reduces the negative resistance. Therefore, it is difficult to achieve sufficient negative resistance at higher frequencies to overcome resonator losses. In this paper, a novel technique is presented to enhance the negative resistance for common collector Colpitts oscillators. First, we analyze the effect of the collector inductor on the negative resistance. Then, we present a novel technique using an inductor to increase the negative resistance further. Then we discuss the effect of the Q-factor of these inductors on the negative resistance. To prove the technique, two Colpitts oscillators were designed at 400 MHz using discrete components. The measured phase noise is -110.19 dBc/Hz and -122.81 dBc/Hz at 100 kHz offset from 400 MHz and 410 MHz respectively and a RF output power of +0.62 dBm and +4.0 dBm respectively directly into single-ended 50 Omega load.

In MMIC circuit design, the transitions and interconnects are essential components for integration and packaging [1-3]. However, the conventional distributed type transition circuits will result in great loss owing to their huge size, most especially in medium and low frequency band. In this paper, a new CPW-to-microstrip transition design based on lumped element circuits is proposed. The optimized design can achieve a return loss of less than 10 dB from 3 to 14 GHz and insertion loss of less than ldB from 3 to 14 GHz.

A novel elastomer probe meant for wafer level packaged device test applications at multi-gigahertz frequencies given tight mechanical constraints such as very fine pitch (of the order of 100 micron) and large pin count (of thousands per square centimeter) is modeled by partial element equivalent circuit (PEEC) method. The model is verified through insertion loss and return loss measurements on a prototype coplanar probe

A novel multi-frequency transformer is developed based on dual frequency transformer reported recently. Different from dual frequency transformer, which has two steep poles, the return loss curve of the transformer developed in this paper has one steep pole with two gentle side poles. This transformer can achieve ultra-wideband because it makes use of big separation ratio between center frequencies as employed in dual frequency transformer. At the same time, the gentle side poles avoid sharp jump of peak values between two adjacent poles. The transmission line analysis shows that the three-pole transformer can achieve 120% bandwidth compared to 60% of dual frequency transformer.

In this paper, a novel dual-band hybrid antenna consists of a CPW-fed inverted-L monopole and a high permittivity rectangular dielectric resonator (DR) is presented. The inverted-L monopole simultaneously acts as an effective radiator and the feeding structure of the DR. The high permittivity rectangular DR can be efficiently excited if its dimensions and the relative position on the monopole are properly determined. By connecting the monopole and the DR in parallel, a dual-band hybrid antenna with compact size is achieved. A prototype antenna has been designed to satisfy the IEEE 802.11 WLAN standards.

A simple, robust but accurate method to extract the thermal resistance of BJT/HBT devices is proposed. It only needs the measured device DC I-V BJT/HBT devices, GaAs HBT, silicon BJT and SiGe HBTs. Compared to the measured results taken from both CW DC measurements and isothermal measurements, the extracted values using our method is in excellent agreement with the conventional method

The objective of this work is to be able to test wafer level packaged devices at 5 GHz given tight mechanical constraints such as very fine pitch (of the order of 100 micron) and large pin count of thousands. Good electrical contact at the wafer level after the attachment of interconnects is needed for producing reliable electrical test results.. This paper describes the details of modeling, fabrication and the test methodology as applied to the electrical characterization of fine pitch and large pin count wafer level packaged devices.

An efficient magnetic current model for the analysis of low temperature cofired ceramics (LTCC) small aperture coupled patch antennas at high frequency is presented. The approach is based on the method of equivalence magnetic current and its closed-form multilayer Green's function in the spatial domain coupled with the method of moments (MoM). Numerical results of the Green's function and return loss of the LTCC small antennas at Ka band are analyzed.

The self- and mutual inductance of a spiral will change significantly with an increase in frequency due to the current redistribution on the metal trace. This phenomenon comes from the skin effect and the simultaneous eddy current. The basic formulae for inductance calculation are thus studied and further improved in this paper. Theories are tested with measured data on sample inductors fabricated on silicon substrate.

A ground-slot coupling technique is applied to design a novel multilayer active hybrid-ring power divider. The prototype consists of three ground slots to couple the signal between circuit layers, and two single-stage HEMT amplifiers to boost the coupled signal. It is tested at C-band with 40% -3dB bandwidth. At 5 GHz center frequency, it has 8 dB small-signal gain and 10 dBm output P1 dB.

A high efficiency power amplifier is implemented using a simplified design method. The approach utilizes small signal S-parameter data only. A high efficiency power amplifier with a maximum power added efficiency of 68.8 %, a nominal power gain of 8.6 dB and 21 dBm output power at 7.5 GHz was implemented. The high efficiency performance is obtained from proper selection of the second harmonic termination for a class AB power amplifier.

A new method for the design of the Marchand balun using microstrip lines is proposed. This new method cuts down significantly on the time required to design a balun. A 1-6 GHz Marchand balun was designed using this method and fabricated Measured and fabricated results show a good match. A bandwidth of 1.5-5.5 GHz was obtained with a phase imbalance of less than 5 degrees.

The accurate modeling of weak avalanche breakdown of HBTs in compact bipolar transistor models for circuit simulation is presented. Based on various device electrical characteristics that are grouped into three classes, a modified VBIC avalanche multiplication model is proposed. By simply replacing one constant avalanche model parameter with current linear dependence, the new model predicts well broad behaviors of breakdown from weak avalanche up into high level injections.

A compact planar ultra-wideband ring monopole antenna with a band-notch feature is presented. The band-notch characteristic is achieved by embedding a quarter-wavelength tuning stub in the circular ring monopole. The notched band is controllable by adjusting the length of the tuning stub. The measured antenna radiation patterns show good omnidirectional performance across the operation bandwidth. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 125–126, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21283

A novel, folded, capacitive-fed microstrip antenna with a length of λ/3 and placed over a cavity backing is proposed. Compared to the small rectangular patch antenna of Luk, our proposed antenna has a large impedance bandwidth of 20.1%. The cross-polarization level is ∼−17 dB. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 240–241, 2001.