A high-power gallium-nitride (GaN) monolithic microwave integrated circuit (MMIC) operating over the 75-100-GHz band is reported. Using an on-chip traveling-wave power-combining network, it achieves a continuous wave output power level of 34 dBm (2.5 W) ±1 dB over the 75-100-GHz bandwidth and a peak power of 3 W at 84 GHz. Operating in a pulsed mode (10% duty), the MMIC chip produces a peak power of 3.6 W at 83 GHz. This work establishes new levels of performance for GaN MMICs at these frequencies. In comparison to the previous work, these results represent improvements in output power, bandwidth, and gain/power flatness with frequency across the full 75-100-GHz band. This paper also presents design details on the combining network and the MMIC not previously reported.

A bi-static E-band (80GHz) electronically scanned imaging radar system has been fabricated and tested. This radar system combines a stare-mode array within a frequency-scanned antenna to extract azimuth and elevation information, while utilizing a frequency modulated CW (FMCW) transceiver to extract range. This unique architecture provides state of the art instantaneous field of view and voxel refresh rates for electronically scanned systems while requiring less RF components than conventional phased array systems, enabling a cost-effective means for volume production of electronically scanned high resolution imaging radar.

A 16-channel receiver module operating at E-band frequencies (80 GHz) is presented. This receiver module is a key component in our 3D FMCW imaging radar. The receiver, with an RF band of 78 to 81 GHz, employs a dual-conversion architecture with an IF band of 4.5 to 7.5 GHz. With a conversion gain of 48 dB, it has demonstrated a noise figure of typically 8 dB. This receiver, employing 115 MMICs and 8 alumina MICs, has established a new level of integration for mm-wave multi-chip modules (MCMs). The size of this module is only 2.375 times 1.355 times 0.63 inch with 16 waveguide inputs spaced 85 mils center-to-center.

Two ICs, specifically designed for commercial applications at K/Ka-band frequencies, are presented. These ICs provide 1 and 2 watts of linear power respectively, gain levels of typically 17 dB and a power added efficiency of 25% at the 1 dB gain compression point. While the RF performance parameters are not state-of-the-art, these compact chips establish new levels for power density, Le. the ratio of output power to chip area. This figure of merit is particularly important for the cost sensitive commercial market.

A power MMIC, employing a unique series bias scheme, is presented operating over the 31 to 33 GHz band. Mounted in a low cost metal-ceramic package and operating at 24 volts, this IC has demonstrated an output power of 0.81 watt with a power-added efficiency of 32%.

The development of a high-gain, high-power, high-efficiency K-band MIC (microwave integrated circuit) power module using four 1.6-mm pseudomorphic InGaAs HEMT (high electron mobility transistor) devices is reported. Power output of 3.2 W with 10 dB gain and 35% power-added efficiency at 3-dB compression was obtained at 20 GHz. The 1-dB bandwidth is 1.7 GHz. The greatly improved power gain and efficiency offer several design advantages in terms of higher SSPA (solid-state power amplifier) efficiency, fewer stages and modules required, and the attendant improved reliability for onboard application at 20 GHz.<>

A hybrid, 2-stage, high electron mobility transistor (HEMT) power amplifier is reported operating over the 32-35-GHz band with a minimum output power of 28 dBm. At 34 GHz, an output power of 0.8 W with an associated power-added efficiency of 26.6% has been demonstrated. Biased for efficiency, this amplifier has demonstrated a power-added efficiency of 32.2% with an output power of over 0.7 W.<>

A fundamental FET oscillator that operates at 92.3 GHz with an output power of 14 mW and with V/sub DS/=3.9 volts is reported. The efficiency is 11% at this point. The data are referenced to the waveguide output port with no corrections for the transition or fixture loss. By tuning the input waveguide short, the device oscillation frequency could be tuned from approximately 91-93 GHz. Maximum power was attained at 92.3 GHz. The output spectrum of this oscillator shows the sideband noise to be approximately -70 dBc/Hz for all offset frequency of 15 kHz. This is comparable to commercial W-band Gunn oscillators.< >

State-of-the-art 60-GHz power performance is reported for ion-implanted InGaAs/GaAs MESFETs with 0.25*200- mu m gate length. At output power of 100 mW, a power-added efficiency of 15% and associated gain of 4.2 dB were obtained and a saturated output power of 121 mW was achieved for the same device. These results are comparable to the best reported millimeter-wave power performance of InGaAs/GaAs pseudomorphic HEMTs.< >

A low noise HEMT amplifier has been developed for operation at 35 GHz. The three-stage amplifier exhibits a noise figure of 3.1 dB with an associated gain of 17.4 +- 0.4 dB across the 34.25 to 35.75 GHz frequency band.

A new N-way broadband planar power combiner/ divider was developed for ultra-broadband MMIC applications utilizing Dolph-Tchebycheff transmission line taper. The combiner/divider demonstrated a 5 to 18 GHz bandwidth with an insertion loss of less than 0.2 dB and an input VSWR of no more than 1.35.

A production technology for high yield and high performance MMIC's has been developed. Two stage X-band power amplifier and low noise amplifiers were used as test vehicles in this producibility study. The power amplifier chips have consistently demonstrated a 1.5 watt output power with 9 dB gain and 20% power added efficiency. The low noise amplifier chips have achieved a reproducible performance of less than 3 dB noise figure with 20 dB gain. Producibility improvement of MMIC chip fabrication has achieved an average yield well in excess of 10%.

A monolithic distributed amplifier (DA) which operates from 2 to 40 GHz is presented. The device has a gain of 4 dB over the entire band with a noise figure of less than 9 dB in K-band and 7 dB at 10 GHz. The output power at 1 dB compression is +12 dBm. Two chips were cascaded to achieve 8 dB gain from 2 to 40 GHz. The seven-section circuit has 476 μm total gate periphery and is fabricated on a 1.1 × 3.2 mm chip.

A low noise FET amplifier has been developed for the 27.5 to 30 GHz communications band using a new 1/4 m gate GaAs FET device. The 3-stage amplifier exhibits a maximum noise figure of 3.2 dB across the 27.5 to 30 GHz band with an associated gain of 23 +-0.5 dB.

A monolithic oscillator was fabricated using conventional planar FET technology. The active device used was a 0.35x60 micron FET fabricated on an active layer formed by ion implantation into an undoped VPE buffer layer. Frequency stability is achieved using either an on-chip microstrip resonant circuit or by adding a 30 mil diameter dielectric resonator directly onto the 50 mil square GaAs chip. With no external tuning the oscillator delivered 0.45 milliwatts at 64 GHz. By using an external E-H waveguide tuner, 0.7 milliwatts of power at 65.7 GHz was achieved. The oscillator was tunable from 55 to 75 GHz by adjusting the source-gate tuning inductor and the drain tuning.

Extremely high frequency (EHF) receivers for military and NASA programs must be small, lightweight, and highly reliable. In connection with recent advances in the development of mm-wave FET devices and circuits, a basis has been obtained for the eventual replacement of diode mixer front-ends by FET preamplifiers in receivers up to 94 GHz. By placing a low noise amplifier in front of the mixer it is possible to achieve a lower system noise figure than that found in conventional mm-wave receivers. A broader bandwidth can also be provided. Attention is given to the receiver configuration, a low noise FET amplifier, an image rejection filter, a dual-gate FET mixer, a FET local oscillator, and a FET receiver.