Recent developments in design of 20 and 44 GHz conformal phased array antennas which use the MMIC technology in conjunction with microstrip array technology are reviewed. A candidate integrated array structure based on a 'tile' approach is described. A fundamental building block of this array is a monolithic subarray consisting of a number of radiating elements, each with its own phase shifter and amplifier on a single GaAs substrate. The array structure contains several thousand radiating elements in a very small area.

Application of MMIC technologies for programs developed in the European Technology and Research Center (ESTEC) is discussed. The ESTEC activities covered the assessment of MMIC capabilities in terms of production yield and reproducibility using a two-stage X-band amplifier, examination of basic design and utilization MMIC requirements for space applications, and development of MMIC devices for future programs. It is concluded that ESTEC has been heavily involved in promoting and developing the MMIC technology and contributed to better understanding of the technology.

The application of arrays of integrated circuit receiver to imaging of microwave and millimeter wave radiation is presented. Overall system concepts and both focal-plane and aperture-plane types of systems are discussed. Several functional block diagrams of the sensors are suggested and some examples of state-of-the-art units are presented

InP-based (AlInAs/GaInAs) high electron mobility transistors (HEMTs) have demonstrated a substantial performance improvement over GaAs-based devices. HEMTs with extrinsic f(T) over 200 GHz, fmax over 300 GHz, and amplifiers with extremely low noise figures and high associated gain have been achieved. A review of the status of this device technology and projections for high performance microwave and millimeter-wave applications will be discussed.

A K-band MMIC LNA and a family of MMIC frequency doublers were designed and fabricated using the planar-doped pseudomorphic InGaAs HEMT technology for future EHF satellite communication terminal transceiver applications. The InGaAs HEMT LNA showed less than 2 dB noise figure and more than 32 dB gain from 21 to 23 GHz. The Ku-, K-, and Q-band MMIC HEMT doublers demonstrated low conversion loss and wideband operation. They showed 10 dBm, 8 dBm, and 0 dBm output powers, and 2.5 dB, 4.5 dB, and 8.6 dB conversion losses at 17.4 GHz, 22.25 GHz, and 43.5 GHz, respectively.

We have fabricated an integrated W-band downconverter using 0.15 micron T-gate lattice-matched InGaAs/InP High Electron Mobility Transistor. The two-stage MIC LNA demonstrated record performance with a minimum noise figure of 3.0 dB and 16.5 dB associated gain at 93 GHz. The active InP HEMT mixer showed 2.4 dB conversion gain and 7.3 dB noise figure at 94 GHz. This is the first reported active mixer conversion gain at W-band. The complete downconverter exhibited 3.6 dB noise figure and 17.8 dB conversion gain at the waveguide input. These state-of-the-art performances demonstrate that a complete W-band MMIC downconverter chip with extremely low noise figure and high conversion gain can be fabricated on the same wafer using the InP HEMT technology.

This paper presents a novel noise parameter extraction technique for MESFETs. All measurements are done with a 50 ohm source and load which allow the FET to be characterized on wafer easily, accurately and quickly. The noise parameter values are extracted using an in-house model extraction CAD tool. This technique has been validated by comparison to noise parameters measured by using tuners. Additionally, LNAs, distributed and feedback amplifier MMICs have been tested and demonstrated excellent correlations between the measured and simulated noise performance up to 20 GHz.

Methods aimed at increasing linearity of a low noise amplifier with specified 1-dB compression point using the spike doped MESFETs are described. Particular attention is given to the effects of FET device parameters on the third order intermodulation (IM3), an MBE spike doped MESFET, spike doped MESFET characteristics, and a three-stage MMIC amplifier. It is concluded that the IM3 can be significantly reduced by choosing the appropriate device and operating the amplifier with optimized device parameters.

Advances in microwave and millimeter-wave power monolithic amplifier technology are reviewed. Device structures and circuit topologies that enhance the efficiency of monolithic power amplifiers for space communication applications are discussed. Mature GaAs MESFETs as well as emerging III-V heterostructure field-effect and bipolar transistors designed for high-efficiency operation are covered. Relative merits of various types of devices for implementation in high performance monolithic amplifiers are discussed.

A monolithic three-stage Ka-band amplifier has been designed and fabricated on a doped channel heterostructure. Devices with gate length of 0.2 micron and gate width of 50, 100, and 250 micron were cascaded. The gate and drain bias networks were also integrated. The small signal gain is 31 dB and the amplifier is capable of an output power of 190 mW with 23 dB gain and 30.2 percent power added efficiency at 31 GHz. This is a record efficiency for a multistage MMIC at this frequency.

Two variable gain MMIC module designs for space applications are described. In the baseline MMIC module which has a maximum gain of 50 dB, with 30 dB of dynamic gain control over 3.7 to 4.2 GHz band, the MMIC chips are mounted in custom using a low-cost ceramic package technology. The custom ceramic package is a hermetic, dual-shielded cavity enclosure with 70 dB measured cavity isolation. The baseline module is considered to be an excellent candidate for insertion into a solid state power amplifier as a predriver circuit. A second module design uses a metal package with a single chip and discrete components mounted within the package and is characterized for application as an ALC circuit. This module has a 20-dB gain with 10 dB dynamic gain control. It is concluded that the insertion of monolithic microwave integrated circuit technology into satellite applications makes it possible to reduce weight, size, and manufacturing time.

We describe an improved heatsink technology fully compatible with a standard MMIC processing that significantly decreases the thermal limitation of the MMIC format. By etching to reduce the substrate thickness by 75 micron only immediately under the active areas of the MESFETs and selectively plating solid gold heatsinks to replanarize the back of the wafer, a 45 percent reduction in the thermal resistance is obtained. Despite a very compact design, 2.4 mm MESFETs fabricated on 100 micron thick substrates demonstrated a thermal resistance of only 18 C/W. Using these devices, a 2 stage 2 watt power MMIC was designed to fit a compact 1.4 mm x 3.25 mm chip footprint. The nominal 2 watt, 7-11 GHz power MMIC amplifier was designed for phased array applications where small size, high power and high efficiency are primary concerns. With fixed off-chip tuning, the MMIC delivers 1.7-2.3 watts with 18-24 percent power added efficiency across the full 7-11 GHz band.

A two-stage Gallium Arsenide (GaAs) monolithic power amplifier has been developed. The main features of the amplifier are the coverage of two distinct frequency bands, X-band and Ku-band; high power output of 800 mW at 2 dB compression at 85 C, and high efficiency, 14 to 20 percent at 85 C. The circuit includes on-chip biasing accessible from both sides of the circuit and is stable under any combination of input/output loads attainable with standard tuners. The amplifier measures 0.109 by 0.120 in. and was fabricated with standard ion-implanted, 0.5 micron gate length MESFETs.

Using spectral domain coupled transmission line calculations and computer programs to generate circuit files for standard circuit analysis programs, a double balanced monolithic mixer with RF/IF overlap has been developed using spiral baluns. This technique can be employed to extend the design of high density MMIC circuits to frequencies greater than 20 GHz.

Using silicon as the substrate material SIMMWIC (Silicon Monolithic Millimeter Wave Integrated Circuit) oscillators and receivers are successfully realized. For the coplanar oscillators a slot is used as the resonant structure in which a monolithically integrated IMPATT diode selectively grown by Silicon molecular beam epitaxy (Si-MBE) acts as the negative resistance device. Pulsed and CW operation of the planar oscillators is achieved in the 90 GHz region. The output power is either radiated from a planar Vivaldi antenna or directly from the resonant slot. Complete receivers with monolithic Schottky diodes together with the antenna are integrated on a single chip.

A new procedure is presented here for simulating large, planar, passive MMIC layouts with reduced computation time using a full-wave/integral-equation based solver. The methodology of this new approach entails characterizing the layout accurately at the subcomponent or block level and accounting for parasitic couplings in a selective manner. Assessments on the accuracy and the computational efficiency of our new approach are presented.

We have developed and fabricated a variety of single-stage coplanar waveguide MMIC amplifiers based on our InP-based AlInAs/GaInAs HEMT device technology. The measured f(t) of 0.15-micron devices was 120 GHz and fmax was 200 GHz. The dc transconductance was greater than 720 mS/mm. The 12-GHz single-stage MMIC amplifier had a noise figure of 1.3 dB with an associated gain of 16.0 dB. A 35 GHz single-stage amplifier had a measured gain of 10.9 dB and a measured input return loss of -14.4 dB. A 60 GHz single-stage amplifier had a measured gain of 8.4 dB and a measured input return loss of -18.4 dB.

GaAs monolithic microwave integrated circuits are reviewed focusing on analytical and experimental work to improve array performance and reliability while reducing the cost. Monolithic array technology is equally applicable to communications and radar systems. In radar applications both transmit and receive functions at the elemental level require a transmit/receive module's physical size to be compatible with 1/2 wave length element spacing. For communication applications, separate aperture are used for transmit and receive to ensure sufficient isolation for full duplex operation. Radar transmitter chains are capable of operating with a saturated power output stage which helps to increase efficiency and minimize DC power. Communication systems place severe linearity constraints on the transmitters and receivers which requires the power amplifier to operate in an ultra-linear fashion.

Direct integration of solid-state sources with planar antennas has made it possible to fabricate monolithic active antennas. This paper reviews the recent developments of integrated circuit active antennas and their applications.

The results of ongoing development programs in the area of advanced satellite antenna technology currently being pursued at COMSAT Laboratories, under the sponsorship of the World Systems Division of COMSAT Corporation, are described. These programs are exploiting the promise of monolithic microwave integrated circuits (MMICs) as they apply to active phased arrays. Performance data on two phased-array programs are presented. The first program involves the development of a 64-element array in which MMICs are used to optimize and reconfigure the radiation pattern performance. The array is capable of generating a single beam and accurately synthesizing a specified radiation performance. The second array program, building on knowledge gained in the first program, addresses the problems of generating multiple beams, as well as the effect of power amplifiers on multicarrier performance. MMICs are employed in the beam-forming matrix and in the distributed 2-W solid-state power amplifiers. This design is capable of forming four simultaneous, independently steerable beams while allowing for flexible power sharing among the beams.

Recent advances in pseudomorphic HEMT MMIC (PMHEMT/MMIC) technology have made it the preferred candidate for high performance millimeter-wave components for phased array applications. This paper describes the development of PMHEMT/MMIC components at Ka-band and V-band. Specifically, the following PMHEMT/MMIC components will be described: power amplifiers at Ka-band; power amplifiers at V-band; and four-bit phase shifters at V-band. For the Ka-band amplifier, 125 mW output power with 5.5 dB gain and 21 percent power added efficiency at 2 dB compression point has been achieved. For the V-band amplifier, 112 mW output power with 6 dB gain and 26 percent power added efficiency has been achieved. And, for the V-band phase shifter, four-bit (45 deg steps) phase shifters with less than 8 dB insertion loss from 61 GHz to 63 GHz will be described.

A set of HEMT MMICs including LNAs and phase shifters has been developed for an all-HEMT 20 GHz phased array receiver applications. These MMICs use state-of-the-art HEMT devices for low noise figure, innovative design techniques for compactness, and proven wafer processing for high yield. The LNA achieved a noise figure of 2.5 dB with an associated gain of 22 dB. The 3-bit phase shifter achieved 6 to 7.8 dB insertion loss for all states. With their performance and high process yield, these MMIC chips can be inserted into a system to demonstrate the next generation phased array performance.

We are developing integrated antennas and receivers for millimeter-wave applications. As the remote-sensing frequencies are pushed higher into the millimeter and submillimeterwave regions, the integrated receivers become very competitive with standard waveguide receivers. The integrated units consist of an antenna integrated directly with a matching network/mixer. Integrated receivers are easier to manufacture, more reliable and much less expensive than waveguide receivers. The integration also allows the use of linear or two- dimensional arrays without a dramatic increase in cost.

A microwave/millimeter wave system-level integrated circuit (SLIC) being developed for use in phased array antenna applications is described. The program goal is to design, fabricate, test, and deliver an advanced integrated circuit that merges radio frequency (RF) monolithic microwave integrated circuit (MMIC) technologies with digital, photonic, and analog circuitry that provide control, support, and interface functions. As a whole, the SLIC will offer improvements in RF device performance, uniformity, and stability while enabling accurate, rapid, repeatable control of the RF signal. Furthermore, the SLIC program addresses issues relating to insertion of solid state devices into antenna systems, such as the reduction in number of bias, control, and signal lines. Program goals, approach, and status are discussed.

Progress in communications satellites and projection of a future satellite system architecture are presented. The advantages of microwave/millimeter-wave monolithic integrated circuit (MMIC) technology as applied to present and future systems are discussed. Examples of MMICs that have been developed for various satellite applications from C- to V-band are also presented.

Approaches for future 'mixed application' monolithic integrated circuits (ICs) employing optical receive/transmit, RF amplification and modulation and digital control functions are discussed. We focus on compatibility of the photonic component fabrication with conventional RF and digital IC technologies. Recent progress at Honeywell in integrating several parts of the desired RF/digital/photonic circuit integration suite required for construction of a future millimeter-wave optically-controlled phased-array element are illustrated.

A proposed Ka-band communications experiment between the Shuttle Orbiter and the Advanced Communications Technology Satellite (ACTS) is described. Monolithic Microwave Integrated Circuit (MMIC) technology is used in both the Orbiter and on the ground. A 25 dB gain circularly polarized phased array transmits low-bit-rate television to ground stations at the Johnson Space Center and the Lewis Research Center.

Ka-band MMIC transmitter arrays are under development at NASA Jet Propulsion Laboratory for future deep space and ground communication needs. A high efficiency full aperture active antenna array is desired to demonstrate solid state array technology for future NASA missions. This paper reports on a 5 watt Ka-band phased array feed and a full aperture active array for a mobile terminal which are being developed to characterize the design tradeoffs and potential of solid state Ka-band MMIC array communication systems.

A low-cost high-data-rate network of terrestrial and satellite communications based on GaAs MMIC chips is discussed. GaAs MMICs provide high levels of integration to meet technical requirements for the high-data-rate modulators and demodulators which has the potential of reducing recurring cost and size and improves system reliability. Gigabit data rate necessary for scientific visualization can be easily justified. Satellite communications is expected to provide link connectivity between the researcher and the supercomputer resources.

NORAD system currently tracks and predicts orbits of space objects of 80 mm or larger in diameter. The small debris of less than 80 mm, traveling at high speed, could cause damage to Space Station or space vehicles. To overcome this problem, a 35 GHz space-based millimeter-wave radar system is proposed to track the particles ranging in size from 4 mm to 80 mm up to a range of 25 Km. The system requires a large phased array which should be developed in monolithic circuits for cost reduction.

This paper presents design and test results of balanced I-band amplifiers realized using GaAs HBT and MESFET technology. Their performance comparison in terms of linearity figure of merit demonstrates that the HBT MMICs can provide high third-order intercept point (IP3) with low dc power consumption. It also provides simplified system architecture requiring only a single dc supply voltage.

Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

Radiation damage to high-electron-mobility transistor (HEMT) structures, and its effect on electrical characteristics, are discussed. Radiation from cobalt 60 gamma and nuclear reactor sources was used on microwave and millimeter-wave monolithic circuits to determine total dose sensitivity. Heavy ions (15-MeV silicon) were used to evaluate other potential damage mechanisms. The dc and RF results for a 60-GHz-band monolithic microwave integrated circuit (MMIC) before and after irradiation are presented. The HEMT structures were found to be as resistant to radiation as previously tested metal-semiconductor field-effect transistors (MESFETs), and no new damage mechanisms were observed.

Capabilities and limitations of MMIC phase shifter technology at microwave and millimeter wave frequencies are reviewed. MMIC-based phase arrays make it possible to integrate active elements at the array face, i.e., to incorporate transmit power amplifiers and/or low noise amplifiers at each antenna element. Active elements make it possible to increase power efficiency and reliability and provide graceful degradation. Monolithic integration of the various transmit/receive functions including phase shifting is considered to be feasible through at least the lower millimeter-wave frequency range (about 30-100 GHz). MMIC integration also allows more flexibility in array design including those that are intended for airborne conformal applications.

To compare the capability of MESFET and HEMT technologies for monolithic microwave integrated circuit (MMIC) implementation we have fabricated and tested discrete field-effect transistors (FETs) and a novel Ka-band monolithic voltage controlled oscillator (VCO). We implemented the circuit with three different active devices: moderate- and high-doped ion-implanted MESFETs (metal-semiconductor FETs) and AlGaAs/GaAs HEMTs (high electron mobility transistors). A comparison of the measured oscillator phase-noise and an independent comparison of the temperature dependence of MESFET and HEMT RF equivalent circuits yields two general guidelines: MESFETs are preferred over HEMTs for applications requiring low phase-noise and temperature insensitive operation.

Details of the design, fabrication, and measured data for three InGaAs HEMT broadband feedback amplifiers are presented. Each amplifier was designed for octave bandwidth operation, but exhibits good performance over slightly larger bandwidths: 2-7 GHz, 5-11 GHz, and 9-19 GHz. The circuits feature compact size, low noise, and high yield. Each circuit measures approximately 2.5 mm x 1.5 mm. Maximum noise figure measured 2.1 dB with 11.8 dB minimum gain for the low-band amplifier, 1.9 dB with 9.9 dB gain for the mid-band amplifier, and approximately 2.5 dB with 8.3 dB gain for the high-band amplifier. RF yields of greater than 70 percent have been achieved.

The progress made in producing low noise MMICs in Ka-band using an ion-implantation technology is reviewed. The technology is characterized by 3.8 dB noise figure with 14-16 dB gain and is suitable for high volume applications where the cost is to be kept low.

A gate feedback oscillator is presented which is motivated by the geometry of the monolithic MESFET device, with a monolithically integrated oscillator in GaAs. This power combining, solid state oscillator can be used as a microwave and millimeter wave source, and in most applications it needs to be tunable in both power and frequency. The tuning can be performed with a separate wafer loaded with varactor diodes, that has an electrically variable reflection coefficient, and is equivalent to a tuning short. Phase control is carried out using optical injection-locking. A single MESFET microstrip oscillator is demonstrated that is optically injection locked at 5 GHz. To characterize the nonlinearity of the device, electrooptic sampling of the gate-source voltage has been performed inside the GaAs FET in a microstrip oscillator and the saturation level has been determined at different bias points.

A compact 5-bit MMIC phase shifter has been developed utilizing FET switches and coplanar waveguide delay lines. The device has constant time delay over a bandwidth of more than 18 percent with an accuracy of +/- 1.2 ps at X-band. An 11.5 GHz version has less than 12 dB of insertion loss for any of its 32 states and an overall chip dimension of 2.25 x 2.50 mm. A 20 GHz version has less than 11 dB of insertion loss and an overall chip dimension of 2.0 x 3.0 mm. Unit-to-unit variation in absolute time delay is less than 2 ps across two wafer lots and four wafers.

A wide band 6 to 18 GHz mixer has been designed and developed for high dynamic range operation. The mixer utilizes monolithic MESFET quad as a mixing element for the double balanced mixer circuit. The baluns have been developed on low dielectric constant substrates and are fully compatible for a planar approach. The mixer circuit exhibits an IF bandwidth of 2 GHz to 6 GHz and has a measured input intercept point of +25 dBm. The fabricated RF and LO baluns have demonstrated an excellent performance in amplitude and phase up to 21 GHZ. The IF baluns demonstrate similar performance from 1 GHz to 1 0 GHz. The design is transferable to milli-meter range. A 0.5 micron gate length MMIC process was used to fabricate the matched quad. GaAs FET's with double recessed channels, for high breakdown and low parasitic resistance, were used.