James J. Brogle

AlGaAs PIN diode multi-octave, mmW switches

The novel use of an AlGaAs/GaAs heterojunction to form a PIN diode, with reduced RF resistance (RS) and no change in junction capacitance (CT)[1]–[3], has been analyzed and employed in the development of several different PIN diode switches of various circuit topologies. Series designs demonstrate improved insertion loss, shunt designs improved isolation, and series-shunt designs improvements in both parameters. These switches demonstrate superior broadband performance, with low insertion loss and high isolation from 50MHz to almost 80GHz, and series-shunt switches exhibit 50% increased input power capability over equivalent homojunction GaAs PIN diode switches.

Heterojunction PIN diode switch

This paper describes the development of a heterojunction AlGaAs/GaAs PIN diode as a replacement for the homojunction GaAs PIN diodes commonly used in microwave systems as a control element for commercial and military switch applications up through millimeter wave frequencies. In particular, a single heterojunction PIN diode, when simulated at a bias of 10 mA in a 50 ohm series configuration, indicates a potential reduction in insertion loss of 37% (Rs) with no degradation in isolation (Cj). This paper describes a switch topology of choice which uses a series-shunt element at the main junction, since it offers the widest bandwidth due to the low zero bias capacitance of the series diode. This simple structure has an upper frequency limitation that is dependent on the electrical distance due to the physical location of the series diode relative to the center of the actual device junction and the maximum isolation achievable by the Cj of a discrete diode. PIN switch circuits and RF probable test structures were processed through our GaAs wafer fab and later tested on-wafer for broadband RF performance from 50 MHz through 40 GHz. A comparison between simulated and empirical results for insertion loss, return loss and isolation demonstrates excellent agreement for isolation and a 10% offset for insertion loss and return loss.

A monolithic, 1000 watt SPDT switch

A monolithic high power, high linearity, broadband, PIN diode switch capable of handling greater than 1000 watts of pulsed peak RF power has been designed and developed using a patented glass/silicon technology. This technology designated HMIC, Heterolithic Microwave Integrated Circuit, has been developed for various mixed signal and control circuit function applications ranging from HF through microwave frequencies. The unique design and fabrication techniques required for the needed improvements in thermal resistance and peak-to-peak voltage handling of this high power switch are discussed in detail. In addition, the results of this development effort in terms of standard switch parameters; insertion loss, isolation, return loss, and power handling are presented in the following paper.

Ka band high power AlGaAs PIN diode switches

In this paper we present the design and performance of millimeter wave MMIC switches in the patented MA-COM AlGaAs heterojunction PIN Diode process that allow us to produce high power and low insertion loss devices. The design process from a reflective SPDT switch to a non-reflective version of the switch, with intense use of HFSS and ADS software, is presented. These switches were designed to meet demanding requirements: low insertion loss less than 0.8 dB, 40dBm peak power and 37dBm CW power, and 30dB isolation.

HMIC 3-D chipscale, surface mount devices

Broadband components continue have the basic issues of fundamental high frequency performance and unit-to-unit reproducibility. While possible solutions to these two basic problems exist, it is universally acknowledged that both the basic semiconductor performance at frequencies above 10 GHz and the unit variation are severely limited by packaging, die attach, and chip and wire assembly techniques. The purpose of this paper is to present a unique, fundamentally different approach to the packaging and monolithic integration of ultra wideband switches which not only includes the electrical input/output but also device thermal heat sinking. This method is based upon a technology, HMIC, which utilizes standard semiconductor wafer scale processes to realize the final monolithic, surface mountable element, in this case a single pole four throw multi octave switch.

Chipscale mmW Switches

The biggest issues facing mmW components continue to be ones of fundamental high frequency performance and unit-to-unit repeatability. While solutions to these two basic issues are complex and multi-faceted, it is universally acknowledged that both the basic semiconductor performance at frequencies above 10 GHz and the unit variation are severely limited by packaging, die attach, and chip and wire assembly techniques. The purpose of this paper is to present a unique, fundamentally different approach to the packaging and integration of mmW components starting with the electrical input/output through final thermal heat sinking. This method is based upon a technology, HMIC, which utilizes standard semiconductor wafer scale processes to realize the final monolithic, chipscale, surface mountable element, in this case an mmW switch.