Gate Mixer Research Articles

A self‐oscillating mixer with double‐conversion structure for 77 GHz applications

ABSTRACTWe demonstrated a novel self‐oscillating up‐conversion mixer with double‐conversion structure in order to overcome a high conversion loss of a self‐oscillating sub‐harmonic up‐conversion mixer. The self‐oscillating double‐conversion mixer consists of a self‐oscillating up‐conversion mixer and an up‐conversion gate mixer, based on two 100 nm pseudomorphic high electron mobility transistors (PHEMTs). The mixer has an operating frequency of 77 GHz due to the double‐conversion of self‐generated fundamental LO frequency of 38.5 GHz. The mixer exhibits a good conversion gain of 3.87 dB and a phase noise of −92.9 dBc/Hz at 10 MHz offset. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1989–1993, 2016

임의유전체 기판을 이용한 주파수 혼합기의 소형화

A size-reduced high frequency mixer designed by adopting artificial dielectric substrate is described in this work. The artificial dielectric substrate is composed by stacking the lower substrate in which a lot of metalized via-holes exist, and upper substrate on which microstrip lines are realized. The effective dielectric constant increases due to the inserted lots of via-holes, and this may be applied to size-reduction of high frequency circuits. In this work, in order to present an application example of size-reduction for active high frequency circuits using the artificial dielectric substrate, a 8GHz single gate mixer is miniaturized and measured. It is described that the basic circuit elements for mixers such as hybrid, low pass filter, and matching networks can be replaced by the artificial dielectric substrate for size-reduction. The final mixer has 55% of size compared to the normal one. The measured average conversion gain is around 3dB which is almost similar result as the normal circuit.

A 1.2 V 15–32 GHz low-power single-balanced gate mixer with a miniature rat-race hybrid

A 15–32 GHz miniature single-balanced gate mixer is proposed and analyzed. It achieves a smaller chip area with acceptable conversion gain and port-to-port isolation. In addition, the design procedure is described in detail. This mixer, fabricated in 90 nm digital CMOS technology, demonstrates a measured conversion loss of 1 dB and higher than 30 dB RF-to-LO port isolation from 17 to 32 GHz, at a local oscillator (LO) driver power of −4.3 dBm. The total dc power consumption is only 6 mW from a 1.2 V supply, including output buffer. The low dc power consumption and LO driver power reduce the power budget, and the proposed miniature rat-race hybrid facilitates integration in a receiver.

60 GHz Double-Balanced Gate-Pumped Down-Conversion Mixers With a Combined Hybrid on 130 nm CMOS Processes

Two 60-GHz compact double-balanced gate-pumped mixers using standard bulk 0.13 ¿m CMOS process are presented. The homodyne and heterodyne mixers utilize small-size combined hybrids and demonstrated a small chip size of 0.8 × 0.85 and 0.7 × 0.7 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , including pads. With 5 dBm LO power, the best measured conversion gains are 1 and 0 dB in the 3 dB bandwidths of 15 GHz from 54 to 69 GHz and 14 GHz from 53 to 67 GHz RF. The LO-to-RF isolations are greater than 45 dB at a low bias of 1.2 V and 12 m A. This is the first demonstration of the double-balanced gate mixer in millimeter wave frequency.

Analysis and Design of Reduced-Size Marchand Rat-Race Hybrid for Millimeter-Wave Compact Balanced Mixers in 130-nm CMOS Process

The analysis and design flow for reduced-size Marchand rat-race hybrids are presented in this paper. A simplified single-to-differential mode is used to analyze the Marchand balun, and the methodology to reduce the size of Marchand balun is developed. The 60-GHz CMOS singly balanced gate mixer and diode mixer using the reduced-size Marchand rat-race hybrid are implemented to verify the design methodology. The monolithic microwave integrated circuit mixers achieve comparable performance with a compact chip size among the reported 60-GHz CMOS mixers.

결합된 결함 접지면 구조(C-DGS)를 이용한 대역 저지 여파기 및 믹서 응용

본 논문에서는 부성 자계 결합을 이용한 C-DGS를 제안하고, 이를 이용하여 차단 특성이 향상된 대역 저지 여파기(Bandstop Filter: BSF)를 설계하였다. 제안된 C-DGS는 부성 자계 결합을 이용하기 위해서 DGS 사이의 거리를 좁힌 구조로 부성 자계 결합의 효과로 인하여 차단 특성이 크게 향상된다. C-DGS를 이용한 BSF는 기존 연구 보고된 양면 BSF의 DGS 및 변형된 마이크로스트립 사이의 거리를 좁힘으로써 DGS 사이에 부성 자계 결합을 발생시킨 구조로 차단 특성은 3단 구조에서 -64.3 dB/GHz, 5단 구조에서 -108 dB/GHz 가지며, <TEX>$4{\sim}11.3$</TEX> GHz의 -10 dB 저지 대역을 가진다. 특히, Bragg 법칙의 최대 반사 조건을 만족하는 BSF의 3단 구조와 비교하여 차단 특성을 3.8배 향상시켰고 크기를 35.2 % 감소시켰으며, 5단 구조와 비교하여 차단 특성을 2.4배 향상시켰고 크기를 40 % 감소시켰다. 또한, C-DGS를 이용한 BSF를 이용하여 단일 게이트 혼합기를 설계하여 6.6 dB의 변환 이득을 가짐을 확인하였다. In this paper, a coupled-defected ground structure(C-DGS) using negative inductive coupling is proposed and a bandstop filter(BSF) using C-DGS is designed and fabricated. The proposed C-DGS is the closely-located DGS cells for the negative coupling, the negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. The proposed BSF utilizing the sharp cutoff response of the C-DGS has a -10 dB rejection band from 4 GHz to 11.3 GHz. A maximum attenuation rate is -64.3 dB/GHz in 3 cell structure, -108 dB/GHz in 5 cell structure. The C-DGS BSF shows the improved attenuation rate 3.8 times in 3 cell structure, 2.4 times in 5 cell structure, Also, the C-DGS BSF is reduced to 35.2 % and 40 % of the DGS BSF, respectively, due to the closely-located DGS cells. We fabricated the single gate mixer using C-DGS BSF. The single gate mixer has 6.6 dB conversion gain.

High-performance 94-GHz single balanced mixer using 70-nm MHEMTs and surface micromachined technology

We reported 94-GHz, low conversion loss, and high isolation single balanced active gate mixer based on 70-nm gate length InGaAs/InAlAs metamorphic high-electron mobility transistors (MHEMTs). This mixer showed that the conversion loss and isolation characteristics were 2.5/spl sim/3.5 dB and under -29 dB in the range of 92.95/spl sim/94.5 GHz, respectively. The low conversion loss of the mixer is mainly attributed to the high-performance of the MHEMTs exhibiting a maximum drain current density of 607 mA/mm, an extrinsic transconductance of 1015 mS/mm, a current gain cutoff frequency (f/sub t/) of 330 GHz, and a maximum oscillation frequency (f/sub max/) of 425 GHz. High isolation characteristics are due to hybrid ring coupler which adopted dielectric-supported air-gapped microstrip line structure using surface micromachined technology. To our knowledge, these results are the best performance demonstrated from 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.

SIMPLIFIED ANALYTICAL EXPRESSION FOR CALCULATING NOISE FIGURE OF HEMT GATE MIXERS

A simplified analytical expression for calculating noise figure of HEMT gate mixers is presented based on superposition method. The contributions of each noise source have been presented. The non-linear behavior of the transistor expressed by the transconductance profile is used to evaluate the noise figure versus LO power. This study is applied to a HEMT gate mixer, tested at 28.5 GHz radio frequency and 4 GHz intermediate frequency. The predicted and the measured noise figures are in good agreement.

Noise optimization in active microwave HEMT mixers

A noise analysis of gate mixers used for down-conversion is presented in this paper. The single sideband (SSB) noise figure is calculated and optimized based on a simplified analytical expression using all noise-source contributions and harmonic-balance simulation. Analytical and simulated input-impedance optimizations are developed to reduce the noise figure. Two mixers are designed with two different configurations (conventional and low-noise configurations) in order to confirm the calculated, simulated, and optimized noise figures. The noise-figure performances are measured and compared for the two configurations. The LO, RF, and IF frequencies chosen for this test are 9.5, 11, and 1.5 GHz, respectively. It is shown that the noise figure is reduced by 4 dB in the low-noise mixer configuration. Good agreement is obtained between calculated, simulated, and experimental noise figures. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 307–311, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20619

A W-band subharmonically pumped monolithic GaAs-based HEMT gate mixer

A W-band high electron mobility transistor (HEMT) subharmonically pumped (SHP) gate mixer is designed with fixed LO frequency operation. it is fabricated on a 4-mil substrate using 0.15-/spl mu/m GaAs pHEMT monolithic microwave integrated circuit (MMIC) process. the on-wafer measurement results show that the best conversion loss is about 4.7 dB in the W-band, as a 11-dbm 42-GHz low observable (LO) signal is pumped. To our knowledge, this is the first result on low conversion-loss W-band MMIC SHP HEMT gate mixer.

Design and fabrication of a single‐ended gate mixer for a down‐converter in wireless applications

AbstractA single‐ended gate mixer with a high conversion gain, low dissipated power, wide dynamic range and good isolation factor is designed and tested. The mixer is composed of a hairpin‐line band‐pass filter, an input/output matching circuit, a GaAs MESFET transistor, and a lumped element low‐pass filter to convert the radio frequency (RF) into an intermediate frequency (IF). In the non‐linearity analysis of a GaAs MESFET, the novel method with a harmonic balance technique is used to analyze the operating characteristics of a mixer circuit. The designed mixer outperforms a general mixer for a down converter in wireless applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 189–193, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10553

Simplified analytical method for predicting conversiongain of HEMT gate mixers

The transconductance profile is the dominant factor in the frequency conversion process in a gate mixer configuration. Based on this property, a simplified analytical expression for the computation of the conversion gain has been developed. Good agreement is obtained between analytical computations and experimental data.

Influence of the source inductance parasitic effect on the conversion gain of an HEMT gate mixer

This paper examines the influence of the presence of source inductance on the conversion gain of a gate mixer. Two effects are observed: degradation of the gain, and an increase of the local oscillator level power necessary to obtain the maximum gain. Nonlinear simulations, theoretical calculations, as well as experimental data demonstrate that these effects become more important in the millimeter-wave range. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 149–151, 1999.

A high-gain 50-GHz-band monolithic balanced gate mixer with an external IF balun

This paper presents a 50 GHz-band high gain monolithic balanced gate mixer. Conversion gain of the mixer is improved by using an external IF balun with high impedance transforming ratio. This paper shows that the IF impedance of the balanced gate mixer can be approximated from a small signal equivalent circuit. The maximum conversion gain of 8.2 dB is achieved at a LO power of 0 dBm. The effectiveness of the described mixer is confirmed experimentally.

Coplanar integrated mixers for 77-GHz automotive applications

For integration in receivers at 77 GHz, three passive mixers, a balanced diode mixer, a single ended and a balanced resistive mixer, as well as an active single-ended gate mixer have been realized in coplanar 0.15-/spl mu/m PM-HEMT technology on GaAs. The passive mixers achieved conversion losses of about 9 dB. The resistive mixers required an LO power of only 3 dBm and the diode mixer 10 dBm for optimum conversion. The gate mixer obtained a conversion gain of 1 dB for an LO power of 6 dBm, but showed higher sensitivity to the IF load.

Noise modeling in MESFET and HEMT mixers using a uniform noisy line model

The aim of this paper is to present a noise model which predicts the noise performance of MESFET and HEMT mixers. The conversion and noise correlation matrices of a FET mixer are calculated using a uniform nonlinear noisy active line concept to describe the FET. This calculation is based on a perturbation analysis of the large-signal noiseless steady state, making it a microscopic nonlinear noise model. This method is applied to the case of a hot HEMT gate mixer and we show that the theoretical results are in agreement with experimental data.

Analysis and design of a multichannel HEMT gate mixer

AbstractThe analysis of the operation of a HEMT gate mixer is presented below. We study the effect of the HEMT nonlinearities on mixer performance by using the nonlinear model in CAD. In particular, the tailoring of an adequate transconductance profile is used to optimize mixer performance for millimeter‐wave realization. © 1995 John Wiley &amp; Sons, Inc.

Nonlinear models for the intermodulation analysis of FET mixers

An accurate, detailed analysis program has been developed for intermodulation distortion (IMD) simulation of FET mixers. This program is very efficient at calculating the IMD from multiple RF inputs. We have proposed a simplified nonlinear model for IMD analysis of FET gate mixers. The accuracy of the simplified model has been verified experimentally using two different MESFET mixers and one HEMT mixer at X band. All the tests show good agreement between measured results and the calculated results for second- and third-order IMD. The simplified model is based on modeling the derivative of the device transconductance by a sum of a Gaussian function and a linear function of the gate voltage. Drain bias dependence is ignored. The advantage of this model is that it can be used for both MESFET and HEMT mixers, and its fitting parameters can be easily determined from a nonlinear characterization of the devices at low frequencies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Subharmonic gate mixer based on a multichannel HEMT

This paper presents the realization and simulation of a new subharmonic gate mixer based on a multichannel HEMT. This device gives the possibility of tailoring the transconductance profile. Two peaks separated by a valley can be obtained. Biasing the device at the bottom of the valley. the IF signal comes from the mixing of the RF signal and the second LO harmonic. This mixer uses half the normal LO frequency and has a minimum conversion loss of 10 dB.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An HEMT with an integrated on-drain capacitor as basis of an hybrid mixer

This paper reports the study of an HEMT, the characteristic of which is to have a decoupling capacitor directly integrated between its drain and source electrodes. It is shown that, with an appropriate design of this basic filtering element, such a device proves to be efficient as for the realization of hybrid gate mixers. An experimental demonstration of this property is given by comparing a HEMT without capacitor with a HEMT with an integrated capacitor. For the latter, the gate length of which is 0.3 μm, it is shown that, at 18 GHz, a 5-dB improvement of conversion gain is provided by the integrated capacitor.