12-GHz-Band GaAs Dual-Gate MESFET Monolithic Mixers

12-GHz-band GaAs dual-gate MESFET monolithic mixers have been developed for use in direct broadcasting satellite receivers. In order to reduce chip size, a buffer amplifier has been connected directly after a mixer IF port, instead of employing an IF matching circuit. The mixer and the buffer were fabricated on separate chips, so that individual measurements could be achieved. Chip size is 0.96X 1.26 mm for the mixer and 0.96X0.60 mm for the buffer. A dual-gate FET for the mixer, as well as a single-gate FET for the buffer, has a closely spaced electrode structure. Gate length and width are 1 µm and 320 µm, respectively. The mixer with the buffer provides 2.9+-0.4-dB conversion gain with 12.3+-0.3dB SSB noise figure in the 11.7-12.2-GHz RF band. Local oscillator (LO) frequency is 10.8 GHz. A low-noise converter was constructed by connecting a monolithic preamplifier, an image rejection filter, and a monolithic IF amplifier to the mixer. The converter provides 46.8+-1.5-dB conversion gain with 2.8+-0.2-dB SSB noise figure in the same frequency band.     

12-GHz-Band Low-Noise GaAs Monolithic Amplifiers

One- and two-stage 12-GHz-band low-noise GaAs monolithic amplifiers have been developed for use in direct broadcasting satellite (DBS) receivers. The one-stage amplifier provides a less than 2.5-dB noise figure with more than 9.5-dB associated gain in the 11.7-12.7-GHz band. In the same frequency band, the two-stage amplifier has a less tlhan 2.8-dB noise figure with more than 16-dB associated gain. A 0.5-µm gate closely spaced electrode FET with an ion-implanted active layer is employed in the amplifier in order to achieve a low-noise figure without reducing reproducibility. The chip size is 1 mm x 0.9 mm for the one-stage amplifier, and 1.5 mm x 0.9 mm for the two-stage amplifier.     

GaAs Dual-Gate FET for Operation Up to K-Band

A high-frequency equivalent circuit model of a GaAs dual-gate FET and analytical expressions for the input/output impedances, transconductance, unilateral gain, and stability factor are presented in this paper. It is found that the gain of a dual-gate FET is higher than that of a single-gate FET at low frequency, but it decreases faster as frequency increases because of the capacitive shunting effect of the second gate. A dual-gate power FET suitable for variable gain amplifier applications up to K-band has been developed. At 10 GHz, a I.2-mm gatewidth device has achieved an output power of 1.1 W with 10.5-dB gain and 31-percent power-added efficiency. At 20 GHz, the same device delivered an output power of 340 mW with 5.3-dB gain. At K-band, a dynamic gain control range of up to 45 dB was obtained with an insertion phase change of no more than +-2 degrees for the first 10 dB of gain control.     

A plastic package GaAs MESFET 5.8-GHz receiver front-end withon-chip matching for ETC system

A plastic package GaAs MESFET receiver front-end monolithic microwave integrated circuit operating at 5.8 GHz is presented in this paper. It has a two-stage low-noise amplifier followed by a dual-gate mixer. Operating at 3 V and 8.3 mA, a conversion gain of 20.4 dB, noise figure of 4.1 dB, and high port-to-port isolations have been achieved. Total chip size of 1.0×0.9 mm² has been achieved through on-chip matching for both RF and local-oscillator ports and the use of simple two-element matching networks for all interstage matching. The 3-dB bandwidth of conversion gain is 1 GHz     

GaAs-Monolithic IC's for an X-Band PLL-Stabilized Local Source

X-band GaAs-monolithic voltage controlled-oscillator (VCO), divide-by-four analog frequency divider, and Wilkinson power splitter have been developed for frequency stabilization of an X-band Iocal source in a phase-locked loop (PLL) system.The VCO has a series feedback configuration and utilizes an optimized design procedure to yield the highest dc-RF efficiency ever reported for a GaAs-monolithic FET oscillator. The frequency divider has a novel structure which applies a dual-gate FET mixer and two RC-coupled FET amplifier stages to establish a closed loop for generating a 1/4 subharmonic component of an input frequency. The Wilkinson power splitter consists of an isolation resistor and two quarter-wavelength lines, which have been realized in both meander and spiral forms. A VCO-driven frequency divider system incorporating these IC's consumes 380-mW total power to provide the 1/4 subharmonic component of the VCO frequency with more than 3-dBm output power over a 10.86-- 11.01-GHz range.     

A high-performance, miniaturized X-band active mixer forDBS receiver application with on-chip IF noise filter

A GaAs monolithic microwave integrated circuit (MMIC) dual-gate FET active mixer at X-band is described that is designed for direct broadcast satellite (DBS) applications. All of the components of the mixer, including biasing circuitry, RF, LO, and IF matching networks, as well as the IF noise filter, are implemented monolithically into a 25-mil×30-mil area. The design was process tolerant, and layout was compact for manufacturability and low cost. The mixer was integrated monolithically into a complete single-chip DBS low-noise block (LNB) converter. The active mixer has a conversion gain of 5.5 dB and a single-sideband noise figure of 8.5 dB. The circuit is manufactured using a 0.5-μm gate length, buried p^- depletion mode MESFET process without substrate-through via holes     

砷化镓双栅场效应管及其在微波电路中的应用

本文简述砷化镓双栅场效应管的基本特性及其在放大器、倍频器.混频器、振荡器、移相器和开关等微波电路中的应用.     

One-chip GaAs monolithic frequency converter operable to 4 GHz

The frequency converter combines a feedback amplifier, a differential amplifier, a double-balanced mixer, a voltage-controlled oscillator, and an IF amplifier on a 1-mm² GaAs chip. The FET circuits were matched by digital IC design rather than by the distributed element network technique, to use the substrate more effectively. Self-aligned WSi/Au gates 1.5 μm long were used, and the resistance in conventional WSi gates was reduced to enhance microwave characteristics. At 4 GHz, the conversion gain is 18 dB, the double-sideband noise is 11.8 dB and the output power is 5.6 dBm     

Experimental comparisons in the electrical performance of long and ultrashort gate length GaAs MESFET's

Electrical properties of GaAs single-gate and dual-gate MESFET's with gate lengths of 1.2 µm and 0.2 µm have been compared. By reducing the gate length to 0.2 µm, a very high zero-gate-bias drain current Idssand a large increase in the pinchoff voltage were observed in both single-gate and dual-gate devices, Idssin the shorter gate FET was found to be very close to the full channel current. Only a slight improvement in the maximum intrinsic gmwas noted in the 0.2 µm FET's. The knee voltage for the zero-gate-bias curve was larger in the shorter gate FET. At low current levels, soft pinchoff and soft saturation behaviors were observed in the very short gate FET's. A striking feature of the GaAs MESFET is that its output conductance at large drain voltages does not degrade with shorter gate lengths.     

GaAs converter IC's for C-band DBS receivers

GaAs downconverter Monolithic Microwave Integrated Circuits (MMICs) for use in C-band direct broadcast satellite (DBS) receivers were developed. The IC consists of four (4) RF functional blocks and a dc bias block. The RF section includes a low noise amplifier, IF amplifier, mixer, and local oscillator. The dc section incorporates an internal dc bias generation circuit to compensate for device parameter fluctuations in wafer processing. The IC makes it easy to design a complete out-door converter unit with only the addition of two low noise FETs, a band pass filter, and an external dielectric resonator. This IC is realized on a small chip of only 1.1 mm×1.6 mm. The gate length of the FET is 0.5 μm. The active layers of the FETs and resistors are formed by an ion-implantation technique. This IC has a 3.0-dB noise figure and a 43-dB conversion gain at 80-mA total current consumption. To realize compact size and low cost, these ICs are offered in 12-pin QFP plastic packages     

A Low-Noise GaAs Monolithic Broad-Band Amplifier Using a Drain Current Saving Technique (Short Paper)

A low-noise and low-power GaAs monolithic broad-band amplifier is proposed and has been developed, which has a new cascade connection with a large gate-width input FET and the other circuits in such a way that the output stage current flows through the input FET. The fabricated amplifier operates on +5-V single supply voltage, and provides a 3.3-dB noise figure, less than 180-mW power dissipation, and a 10-MHz--2.0-GHz bandwidth with 16-dB gain.     

X-Band Integrated Circuit Mixer with Reactively Terminated Image

An X-band mixer using GaAs Schottky barrier diodes with a thin-film 500-MHz IF preamplifier was developed using hybrid microwave integrated circuit techniques. The balanced mixer had filters to provide a short circuit at the image frequency. The entire mixer preamplifier occupied an area of only 0.38 square inches and had a noise figure of 6.7 dB which corresponded quite closely to the theoretical noise figure considering all losses. The thin-film IF amplifier alone had a 2.2-dB noise figure and the mixer IF amplifier coupling network had a loss of 0.4 dB.     

X-Band Integrated Circuit Mixer with Reactively Terminated Image

An X-band mixer using GaAs Schottky barrier diodes with a thin-film 500-MHz IF preamplifier was developed using hybrid microwave integrated circuit techniques. The balanced mixer had filters to provide a short circuit at the image frequency. The entire mixer preamplifier occupied an area of only 0.38 square inches and had a noise figure of 6.7 dB which corresponded quite closely to the theoretical noise figure considering all losses. The thin-film IF amplifier alone had a 2.2-dB noise figure and the mixer IF amplifier coupling network had a loss of 0.4 dB.     

A 22-GHz-band low-noise down-converter for satellite broadcastreceivers

A simple low-cost and high-performance 22 GHz band down-converter developed for a direct-to-home satellite broadcasting system is discussed. The down-converter consists of a low-noise high electron mobility transistor (HEMT) preamplifier, an image recovery mixer with a particular structure using dielectric resonator filters, a 21.4 GHz GaAs FET oscillator stabilized by a dielectric resonator, and an IF amplifier. These components are fully integrating using microwave integrated circuit technology into a small size. A total noise figure of less than 2.8 dB is obtained over the 22.5-23.0 GHz frequency range. The local oscillator achieves a frequency variation of less than 600 kHz_p-p over a temperature range of -20° to +60°C     

A K-Band GaAs FET Amplifier with 8.2-W Output Power

An 8.2-W GaAs FET amplifier with 38.6+-0.5-dB gain over a 17.7-19.1 GHz frequency band has been developed. This amplifier combines the outputs of eight multistage amplifier modules utilizing a radial combiner. This state-of-the-art power level has been achieved with AM/PM of less than 2°/dB. The third-order intermodulation products at 1-dB gain compression were 20 dBc, and variation in group delay over the frequency band was less than +-0.25 ns. Tests show that the amplifier is unconditionally stable and follows the graceful degradation principle.     

0.2 Micron length T-shaped gate fabrication using angle evaporation

A new technique has been developed to generate sub-half-micron T-shaped gates in GaAs MESFET's. The technique uses a single-level resist and an angle evaporation process. By using this technique, T-shaped gates with lengths as short as 0.2 µm near the Schottky interface have been fabricated. Measured gate resistance from this structure was 6.1 Ω/mm gate width which is the lowest value ever reported for gates of equal length. GaAs single- and dual-gate MESFET's with 0.3 µm long T-shaped gates have also been fabricated. At 18 GHz, maximum available gain of 9.5 dB in the single-gate FET and maximum stable gain of 19.5 dB in the dual-gate device have been measured.     

A wide-band RF front-end for multiband multistandard high-linearity low-IF wireless receivers

A wide-band radio-frequency (RF) front-end is designed with a balanced combined low-noise amplifier and a switching mixer (a low-noise converter) in an RF Si-bipolar process with an f/sub T/ of 25 GHz. The circuit achieves 20-dB conversion gain, higher than -4.5-dBm RF-to-IF IIP/sub 3/ (+15.5-dBm OIP/sub 3/) and less than 3.8-dB double-side-band noise figure in 900-MHz (e.g., GSM) and 1.9-GHz (e.g., WCDMA) frequency bands. The -1-dB compression point is -20 dBm at 13-mA DC current consumption from a single 5-V supply. The local-oscillator leakage to the input is less than -56 dBm in the 900-MHz band and less than -63 dBm in the 1.9-GHz band. The -3-dB bandwidth of the amplifier is larger than 3 GHz and a wide-band matching at the input with -10 to -41-dB S/sub 11/ is achieved in the frequency bands of interest by applying a dual-loop wide-band active feedback. The die area is 0.69 /spl times/ 0.9 mm/sup 2/. The circuit is suitable for area-efficient multiband multistandard low-IF receivers.     

A low-noise 1.2–1.8 GHz cooled GaAs FET amplifier

A low-noise 1.2–1.8 GHz cooled GaAs FET amplifier with mixer bias circuit is reported. The amplifier noise temperature obtained at an ambient temperature of 20 K in the frequency range of 1.2–1.7 GHz is 10K. The lowest noise temperature is 4K. The gain is about 30 dB. An automatic measuring instrument for noise temperature was designed. The noise effect of the input cable and the error analysis of the total measurement were made. The total measurement error is 2 K.     

44-GHz monolithic GaAs FET amplifier

Millimeter-wave monolithic GaAs FET amplifiers have been developed. These amplifiers were fabricated using FET's with MBE-grown active layers and electron-beam defined sub-half-micrometer gates. Source groundings are provided through very low inductance via holes. The single-stage amplifier has achieved over a 10-dB gain at 44 GHz. A 300-µm gate-width amplifier has achieved an output power of 60 mW with a power density of 0.2 W per millimeter of gate width.     

Submicrometer self-aligned dual-gate GaAs FET

Experimental results show that it is possible to fabricate dual-gate GaAs FET's, with Lg1= 0.6 µm and Lg2= 1.3 µm, using conventional photoprocessing equipment, masks, and alignment tolerances. The initial source mesa establishes both the source and drain edges during the ohmic contact metal deposition. These two edges establish the lengths and positions of the two gates in the channel, during the two subsequent evaporations. Initial experimental devices gave reasonably good small-signal microwave performance: 8-dB packaged net gain with less than 6-dB simultaneous noise figure, at 6 GHz.