A compact full MMIC module for Ku-band phase-lockedoscillators

A compact Ku-band phase-locked oscillator module has been developed in a full MMIC (monolithic microwave integrated circuit) configuration. The module includes an MMIC voltage-controlled oscillator, an analog frequency divider, and interstage amplifiers. The constituent monolithic chips are integrated in a very small single-package module and operate at the target frequencies without any external trimming or matching network. The oscillator is tuned more than 1 GHz with a constant output amplitude. The frequency-divided output is also obtained over the whole tuning range. Spurious output is not found at any frequency up to 22 GHz. In spite of the very low-Q factor of GaAs monolithic circuitry, the oscillator phase noise exhibited is less than -80 dBc/Hz, due to the high-gain, high-speed phase lock     

Integration of high-Q GaAs varactor diodes and 0.25 μmGaAs MESFET's for multifunction millimeter-wave monolithic circuitapplications

Two technologies are demonstrated whereby high-Q, vertical-structure, abrupt-junction varactor diodes are monolithically integrated with 0.25-μm GaAs MESFETs on semi-insulating GaAs substrates for multifunction millimeter-wave monolithic circuit applications. Diodes with various anode sizes have been realized with measured capacitance swings of >2.1:1 from 0 V to -4 V and series resistances of approximately 1 Ω. Diodes having a zero bias capacitance of 0.35 pF have Q's of >19000 (50 MHz) with -4 V applied to the anode. Under power bias conditions, the MESFETs have a measured gain of >6 dB at 35 GHz with extrapolated values for f _t and f_max of 32 GHz and 78 GHz, respectively. Using these technologies, a monolithic Ka-band voltage controlled oscillator (VCO) containing a varactor diode, a 0.25-μm GaAs MESFET, and the usual MMIC passive components has been built and tested. At around 31 GHz, the circuit has demonstrated 60-mW power output with 300 MHz of tuning bandwidth     

Multifunction W-band MMIC receiver technology

The development of a W-band (75-110 GHz) monolithic receiver, culminating in a three-chip multifunctional monolithic microwave integrated circuit (MMIC) receiver front-end, is described. The heart of the receiver is a four-channel multiplexer, with each channel possessing its own single balanced mixer and low-noise IF amplifier, all integrated onto a single GaAs chip. Two dual-channel monolithic Gunn oscillators with the drive level and spectral parity to meet system requirements have been developed. The key to the development of the monolithic front-end has been to ensure process compatibility between individual components and the careful partitioning of the chip architecture     

Effects of solar transit in Ku-band VSAT systems

Behavior of networks of very small aperture satellite terminals (VSATs) operating at Ku band during the solar transit period, is compared to more traditional C or Ku-band satellite networks. Based on analyses and experiments, it is explained why solar transit outages are rarer in Ku-band VSAT systems than conventional satellite communications systems. In many cases, Ku-band VSAT systems will operate through periods of Sun transits without any significant increase in transmission error rates or incidences of link outages     

A monolithic Ka-band 0.25 μm GaAs MESFET transmitterfor high volume production

A monolithic Ka-band transmitter consisting of a voltage-controlled oscillator (VCO) and a power amplifier using 0.25 μm MESFET technology has been developed for high volume production. An output power of 21.5 dBm at 35.4 GHz with a tuning range of 600 MHz has been achieved. Hundreds of these monolithic transmitters have been fabricated, and an RF yield of 40% has ben achieved from the GaAs MMIC pilot line based on the total number of wafers started. The high yield obtained from this high level integration of multifunctional MMIC chips indicates the maturity of the design and processing capability of millimeter-wave (MMW) GaAs MESFET technology     

Large-signal computer-aided analysis and design of silicon bipolarMMIC oscillators and self-oscillating mixers

A large-signal analysis and design of silicon bipolar monolithic microwave integrated circuit (MMIC) feedback oscillators and self-oscillating mixers are discussed. Emphasis is placed on the modeling of the active and passive devices and the large-signal analysis and design of nonlinear circuits using SPICE. Measured and simulated data of a C-band self-oscillating mixer are presented     

Interference effects on Space Station Freedom and Space Shuttleorbiter Ku-band downlinks

The Space Shuttle orbiter (SSO) Ku-band single access return (KSAR) link and the Space Station Freedom (SSF) KSAR link via the tracking and data relay satellite system (TDRSS) use the same carrier frequency. The interference between spacecraft is minimized by opposite antenna polarizations and by TDRSS antenna beam pointing, but if the SSF and SSO are in close proximity, it is expected that mutual interference will be significant. It is shown that a simplified analytical approach will yield adequate accuracy for the expected range of operating conditions. Relative degradation in bit-energy-to-thermal-noise power spectral density ratio to achieve a 10^-5 coded bit-error probability is determined to be 4 dB for the Ku-band SSO-to-TDRS I-channel return link with a 4.5-dB effective signal-to-interference total power ratio (S/I) when the Ku-band SSF-to-TDRS return link interferes. For the Ku -band SSF-to-TDRS return link, both analysis and simulation results yield a relative signal degradation of 0.4 dB at the effective S/I=21.6 dB     

High-speed, 100+W RF switches using GaAs MMICs

A low-loss, inductive gate bias network structure which allows a very high stacking level of FET devices for high-power RF switching applications is reported. The design, implementation, and performance of S- and C-band SPDT switches based on this structure are described. Multiple GaAs MMIC chips integrated into a suspended-substrate hybrid circuit are used. At S-band, switch risetimes/falltimes of less than 40 ns and an RF power handling capability of 300 W CW have been demonstrated. This input signal level could be maintained during the switch state transitions (hot-switching), while being switched between the two output ports at rates of up to 500 kHz     

Optimum field theory design of broad-band E-plane branchguide phase shifters and 180° couplers

Optimum rectangular waveguide E-plane branch guide phase shifters and 180° branch guide couplers are designed with the rigorous method of field expansion into normalized eigenmodes. The design includes both the higher order mode interaction between the step discontinuities and the finite step and branch heights. The phase shifter design applies the Schiffman principle to branch guide couplers where two ports are short-circuited. The 180° coupler design combines the advantage of the broadband potential of multiple-branch couplers with the low-insertion-loss qualities of E-plane stub-loaded phase shifters. A computer-optimized phase shifter prototype for the waveguide Ku-band (12-18 GHz) shows a 90°±1° differential phase shift with reference to an empty waveguide within about 23% bandwidth. Five-branch three-stub coupler prototypes, designed for 3±0.2 dB coupling, for the waveguide Ku- and Ka-bands (26-40 GHz) achieve a 180°±1° differential phase shift at the output ports within about 19% bandwidth, as well as more than 30 dB isolation and return loss. The theory is verified by measured results     

Novel unilateral circuits for MMIC circulators

A circuit which is equivalent to a four-port circulator with one port terminated, called a quasi-circulator, is proposed. The quasi-circulator can replace a conventional circulator even though it is not a complete circulator. Examples of novel three-port unilateral circuit modules, called quasi-circulator modules, which are the main part of the quasi-circulator are presented to realize very wide band circulators in monolithic microwave integrated circuit (MMIC) form without using ferrite materials and external magnets. The proposed modules are composed of an active out-of-phase divider and an active in-phase combiner or an active in-phase divider and an active out-of-phase combiner. The modules have many variations. All are very small and operate over a very wide frequency range. Two types of quasi-circulator modules that have very broadband operation up to X or Ku band are demonstrated. A quasi-circulator is also demonstrated. It is shown how an active circulator is realized by quasi-circulator modules     

60-GHz pseudomorphic-MODFET low-noise MMIC amplifiers

The development of V-band low-noise monolithic microwave integrated circuits (MMICs) based on pseudomorphic modulation-doped FETs (P-MODFETs) is presented. These dual-stage MMICs incorporate P-MODFETs, with 0.35-μm×60-μm gates, as the active elements, electron-beam-written tuning elements, and DC-blocking and bias networks. The dual-stage chips exhibited a maximum gain of 10.2 dB at 59.5 GHz and a minimum noise figure of 5.3 dB, with an associated gain of 8.2 dB at 58.2 GHz. A cascaded four-stage amplifier using two MMIC modules exhibited 5.8-dB minimum noise figure with an associated gain of 18.3 dB at 58 GHz and up to 21.1 dB of maximum gain     

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     

X-band HBT VCO with high-efficiency CB buffer amplifier

A monolithic AlGaAs-GaAs HBT VCO with common-base (CB) buffer amplifier was demonstrated at X-band. Overall efficiency of 30% was achieved with 93-mW output power at 9.8 GHz. The MMIC chip is only 1 mm×2 mm, including the monolithic varactor diode. The circuit design offers several unique advantages: (1) the CB buffer amplifier reduces the frequency-pull effect from the external load; (2) the design for the oscillation condition and the output impedance match for power are separated; and (3) the overall efficiency can be high. A step-by-step design procedure is discussed     

High-efficiency Ku-band HBT MMIC power amplifier

A Ku-band monolithic HBT power amplifier was developed using a metal-organic chemical vapor deposition (MOCVD)-grown AlGaAs/GaAs heterojunction bipolar transistor (HBT) operating in common-emitter mode. At a 7.5 V collector bias, the amplifier produced 0.5 W CW output power with 5.0 dB gain and 42% power-added efficiency in the 15-16 GHz band. When operated at a single frequency (15 GHz), 0.66 W CW output power and 5.2 dB of gain were achieved with 43% PAE     

Multifunction SAG process for high-yield, low-cost GaAs microwaveintegrated circuits

A new fully planar, multifunction refractory self-aligned gate (MSAG) technology suitable for the fabrication of GaAs small-signal and power microwave monolithic integrated circuits (MMICs) is demonstrated in a manufacturing environment. Data on the distribution of DC and RF performance and yield for pilot production of discrete FETs and MMICs are presented. The heart of the MSAG process is a planar, self-aligned gate FET. It uses a refractory TiWN Schottky gate and exhibits high performance for small-signal microwave, power microwave, and digital circuit applications. Lots with good wafer yields have demonstrated average chip yields on PCM good wafers of 45%, 49%, and 36% for 2-10-GHz distributed amplifiers, 1-W C-band power amplifiers, and 4-W power amplifiers, respectively     

Synthesis techniques for high performance octave bandwidth 180°analog phase shifters

Novel techniques for synthesizing 180° analog reflection-type phase shifters, with ultra-low phase and amplitude error characteristics, over a very wide bandwidth, are presented. The novel approach of cascading stages, where the nonlinear performance of each stage complements those of the others, results in a significant advance in the linearity performance of traditional reflection-type phase shifters. In this work, it is shown by theoretical analysis that three conditions must be satisfied by the reflection terminations in order to achieve the desired response. The theoretical conditions and subsequent design equations are given. Simulation results for a two-stage Ku -band cascaded-match reflection-type phase shifter show that a very low maximum phase error and amplitude error of ±2.4° and ±0.21 dB, respectively, can be achieved over a full octave bandwidth. Since the complexity of the overall topology is reduced to a minimum, the device appears insensitive to process variations and ideal for both hybrid and MMIC (monolithic microwave integrated circuit) technologies     

Design and performance of octave S/C band MMICT/R modules for multi-function phased arrays

A complex wideband transmit/receive module that achieves performance levels superior to any MMIC module is described. Peak performance within the octave 3.0 to 6.0 GHz band includes a power output of 21 W at S-band and 19 W at C-band, a noise figure of 3.9 to 5.0 dB, 30 to 38 dB of receive gain, 25 to 26 dBm output IP₃, 40 dB of gain control in 256 steps, dual receive channels with independent amplitude and phase control, and an 8-bit phase shifter with less than 1 degree calibrated RMS phase error. Total GaAs area is 146 mm² with 170 mm of total gate periphery. The module incorporates a compact digital interface, requires only three supply voltages, and utilizes advanced packaging techniques, resulting in a size compatible with a grating lobe free grid spacing     

Technology related design of monolithic millimeter-wave Schottkydiode mixers

The development of monolithic millimeter-wave Schottky diode mixers based on technological parameters is described. The complete equivalent circuit of the monolithic Schottky diode is calculated taking into account the semiconductor layer structure and the device geometry. This model has been used in a harmonic balanced software for designing monolithic single balanced mixers. In V-band a minimum DSB noise figure of 3.3 dB and a minimum conversion loss of 6 dB have been achieved. In W-band a minimum DSB noise figure of 4 dB and a minimum conversion loss of 7 dB have been obtained     

A Q-band monolithic balance resistive HEMT mixer usingCPW/slotline balun

A Q-band balanced, resistive high-electron-mobility-transistor (HEMT) mixer has been developed for integration in monolithic millimeter-wave receivers. The mixer consists of two AlGaAs/GaAs HEMTs, a coplanar-waveguide (CPW)-to-slotline local oscillator (LO) balun, and an active IF balun. CPWs are used to eliminate the backside or via-hole process step, which increases the circuit yield and shortens the processing time. The conversion loss of the mixer while downconverting a 42-46-GHz RF to a 2.3-3.2-GHz IF is between 4 and 8 dB using an LO drive of 14 dBm. A 17.5-dBm input two-tone third-order intermodulation intercept point is achieved with an LO drive of 10.5 dBm, while a 5.5-dBm input, 1-dB compression point can be achieved with an LO drive of 14 dBm. This is the first reported monolithic CPW resistive HEMT mixer operating at Q-band frequencies     

TOPEX ionospheric height correction precision estimated fromprelaunch test results

Free electrons in the ionosphere will lengthen the electromagnetic path between the TOPEX/Poseidon altimeters and the ocean surface. The path delay is proportional to the total electron content of the ionosphere along the line of sight between the altimeter and the surface. Since these ionosphere delays are also inversely proportional to frequency squared, the nearly simultaneous use of both Ku-band (13.6-GHz) and C-band (5.3-GHz) TOPEX altimeters permits a first-order correction for ionospheric delays. Using results from prelaunch ground testing of the TOPEX satellite altimeters, the authors present the residual height tracking noise after application of the ionosphere correction algorithm. Results are presented as function of ocean significant wave height and for both the 320-MHz and 100-MHz bandwidth of the C-band altimeter