Michael G. Case

Si/SiGe HBT technology for low-cost monolithic microwave integrated circuits

This silicon-based microwave integrated-circuit technology is suitable for implementation of high-performance low-cost active circuits from 5-25 GHz. This technology promises to dramatically reduce the cost of microwave integrated circuit technology by utilizing manufacturable, high-yield, silicon IC processing, and at the same time enable more highly integrated implementations of microwave transceiver components. A variety of microwave integrated circuits implemented in this technology include mixers, frequency dividers, amplifiers and VCOs, demonstrating feasibility of silicon integrated circuit technology for implementation of low-cost integrated circuits in the upper microwave spectrum.

Architecture, design, and test of continuous-time tunable intermediate-frequency bandpass delta-sigma modulators

This paper examines the architecture, design, and test of continuous-time tunable intermediate-frequency (IF) fourth-order bandpass delta-sigma (BP /spl Delta//spl Sigma/) modulators. Bandpass modulators sampling at high IFs (/spl sim/100 MHz) allow direct sampling of the RF signal-reducing analog hardware and make it easier to realize completely software programmable receivers. This paper presents circuit design of and test results from continuous-time fourth-order BP /spl Delta//spl Sigma/ modulators fabricated in AlInAs/GaInAs heterojunction bipolar technology with a peak unity current gain cutoff frequency (f/sub T/) of 80 GHz and a maximum frequency of oscillation (f/sub MAX/) of about 130 GHz. Operating from /spl plusmn/5-V power supplies, a fabricated 180-MHz IF fourth-order /spl Delta//spl Sigma/ modulator sampling at 4 GS/s demonstrates stable behavior and achieves 75.8 dB of signal-to-(noise+distortion)-ratio (SNDR) over a 1-MHz bandwidth. Narrowband performance (/spl sim/1 MHz) performance of these modulators is limited by thermal/device noise while broadband performance (/spl sim/60 MHz), is limited by quantization noise. The high sampling frequency (4 GS/s) in this converter is dictated by broadband (60 MHz) performance requirements.

A high-gain monolithic D-band InP HEMT amplifier

A three-stage monolithic amplifier has been developed which exhibits a measured small-signal gain of 30 dB at 140 GHz. The circuit employs 0.1-/spl mu/m AlInAs-GaInAs-InP HEMT devices with 150 /spl mu/m gate peripheries, and occupies a total area of 2 mm/sup 2/. Measured gain exceeds 10 dB from 129-157 GHz and 5 dB up to 184 GHz. This is the highest gain per stage ever reported in a transistor amplifier operating at these frequencies.

A fully integrated 43.2 Gb/s clock and data recovery and 1:4 DEMUX IC in InP HBT technology

A 43.2 Gb/s CDR/DMUX IC implemented in InP HBT technology is fully integrated, requiring only a single external capacitor for complete functionality. Sensitivity is 27 mV/sub p-p/ differential with a BER of 10/sup -12/. The IC exceeds extrapolated SONET jitter tolerance specifications, operates with a 3.3 V power supply, and dissipates 3.3 W in 10.2 mm/sup 2/.

High-performance W-band GaAs PIN diode single-pole triple-throw switch CPW MMIC

We present the device technology, design techniques, and circuit performance of a W-band single-pole triple-throw switch implemented in a coplanar waveguide (CPW) GaAs PIN diode MMIC technology. This switch provides more than 20 dB isolation and less than 1.5 dB insertion loss over the 75 to 85 GHz range, and more than 16 dB isolation and less than 1.6 dB insertion loss over the entire 75 to 110 GHz band. To our knowledge, this is the first report of a W-band CPW SP3T switch with state-of-the-art performance.

A comparison of W-band MMIC mixers using InP HEMT technology

This paper compares the performance of three different W-band mixer designs in the same InP HEMT technology. A resistive HEMT mixer, an active HEMT mixer, and a rat-race diode mixer are designed and measured for conversion, intermodulation and noise performance for an LO frequency of 94 GHz and IF frequencies ranging from 0.5 to 5 GHz. This is the first direct comparison of three high-performance W-band mixers fabricated in the same InP HEMT technology.

High-efficiency GaAs-based pHEMT power amplifier technology for 1-18 GHz

Performance and reliability data for a high-efficiency microwave power amplifier design utilizing AlGaAs-InGaAs-GaAs pHEMTs are reported. A single stage MIC amplifier fabricated with a 5.6 mm gate width pHEMT resulted in P/sub out/=2.5 W and PAE=73% at 4 GHz. Twenty three amplifiers with similar performance were built with devices from 4 different wafer lots. Currently, these amplifiers are undergoing an RF lifetest and have shown no change thus far to the 2000 h point. This GaAs-based pHEMT device technology supports amplifier module designs in the 1-18 GHz frequency range with output powers up to 20 W.

Low-cost high-performance W-band LNA MMICs for millimeter-wave imaging

The main limitation to the sensitivity of a radiometer or imager is its equivalent noise temperatures, Te. Placing a low noise amplifier (LNA) at a radiometers front end can dramatically reduce Te. LNA performance has steadily improved over recent years, and here we report on a W-band LNA with the lowest Te measured at room temperature. Furthermore, we present statistical RF data showing high yield and consistency for future high volume production that is needed for commercial radiometric imaging array applications such as security screening, aircraft landing, and other systems.

A 49.2 GHz HEMT static frequency divider using an analog/microwave design approach

Although current gain cutoff frequencies (f/sub T/) of both HEMT and HBTs are comparable and f/sub MAX/ for HEMTs is considerably higher, the highest speed static dividers have been reported in InP-based HBT technology. Higher transconductance of HBTs at smaller sizes compared to HEMTs results in compact circuits and lower interconnect load. Careful management of this interconnect load through an innovative microwave/analog design approach has resulted in a static divide-by-two circuit in InP HEMT technology operating at 49.2 GHz. To our knowledge this is the highest frequency of operation for a fully static divider in HEMT technology - even exceeding results obtained on faster devices with smaller gate lengths.

The Effects of Si-Micromachined On-Wafer Packaging on the Performance of K-Band Circuits

This paper presents results from a study on the effect of Si-micromachined packaging on the performance of K-band circuits. Components inclduding interconnects and stubs have been fabricated using finite ground coplanar (FGC) transmission lines and results indicate that nonmetalized air cavities introduce fewer parasitics as compared to metalized air cavities. Flip-chip devices have been incorporated to design a packaged 3-stage low noise amplifier (LNA). The performance of flip-chip Indium Phosphide (InP) high electron mobility trnsistors (HEMTs) in the host substrate environment is measured and used to design the packaged LNA for desired performance.