Joel M. Andrews

A Silicon-Germanium Receiver for X-Band Transmit/Receive Radar Modules

This work investigates the potential of commercially-available silicon-germanium (SiGe) BiCMOS technology for X-band transmit/receive (T/R) radar modules, focusing on the receiver section of the module. A 5-bit receiver operating from 8 to 10.7 GHz is presented, demonstrating a gain of 11 dB, and average noise figure of 4.1 dB, and an input-referred third-order intercept point (HP3) of -13 dBm, while only dissipating 33 mW of power. The receiver is capable of providing 32 distinct phase states from 0 to 360deg, with an rms phase error < 9deg and an rms gain error < 0.6 dB. This level of circuit performance and integration capability demonstrates the benefits of SiGe BiCMOS technology for emerging radar applications, making it an excellent candidate for integrated X-band phased-array radar transmit/receive modules.

The Effects of Irradiation Temperature on the Proton Response of SiGe HBTs

We compare, for the first time, the effects of 63 MeV protons on 1st generation and 3rd generation SiGe HBTs irradiated at both liquid nitrogen temperature (77 K) and at room temperature (300 K). The 1st generation SiGe HBTs irradiated at 77 K show less degradation than when irradiated at 300 K. Conversely, the 3rd generation SiGe HBTs exhibits an opposite trend, and the devices irradiated at 77 K show enhanced degradation compared to those irradiated at 300 K. The emitter-base spacer regions for these two SiGe technologies are fundamentally different in construction, and apparently are responsible for the observed differences in temperature-dependent radiation response. At practical circuit biases, both SiGe technology generations show only minimal degradation for both at 77 K and 300 K exposure, to Mrad dose levels, and are thus potentially useful for electronics applications requiring simultaneous cryogenic temperature operation and significant total dose radiation exposure

A High-Gain, Two-Stage, X-Band SiGe Power Amplifier

SiGe technology is becoming well-known for its capabilities as a high-speed IC design platform, and is being increasingly employed to address a wide variety of communications circuit applications. Unfortunately, the ever-increasing speed of the requisite SiGe transistors comes at a cost that significantly constrains their use in power amplifier design: available breakdown voltage. We demonstrate here that by using an optimized cascode amplifier architecture employing both the high speed (low breakdown voltage) and high breakdown voltage (low speed) SiGe transistors, one can relax these design constraints considerably. Using this approach, a two stage, X-Band amplifier has been fabricated exhibiting maximums of more than 40 dB of stable gain, an output power greater than 20 dBm, and a power-added efficiency of 25% over the X-band operating frequency of 8.5 to 10.5 GHz, and is suitable for emerging X-band phased array radar applications.

An 850 mW X-Band SiGe power amplifier

An 850 mW SiGe power amplifier operating at X-Band (8.5-10.5 GHz) frequencies with over 11 dB of gain and 18% PAE is presented. This SiGe PA was implemented in a commercially-available, third-generation 130 nm 200 GHz SiGe BiCMOS platform using a hybrid high-breakdown / high-speed cascode pair to enhance voltage swing.

Compact Modeling of Mutual Thermal Coupling for the Optimal Design of SiGe HBT Power Amplifiers

Most bipolar-transistor compact models incorporate some level of self-heating capability in order to determine the impact of thermal effects on circuit performance. Techniques for predicting mutual-thermal-coupling effects, however, are not readily available within most commercial CAD platforms. Presented in this brief is a technique which allows for the easy modification of design-kit-supplied models to predict and optimize mutual thermal coupling using commonly available CAD tools such as Cadence and Spectre.

Comparison of Shunt and Series/Shunt nMOS Single-Pole Double-Throw Switches for X-Band Phased Array T/R Modules

This paper compares the performance of shunt and series/shunt single-pole double-throw nMOS switches designed in a 0.13 mum SiGe BiCMOS process for X-band phased array transmit/receive modules. From 8.5 to 10.5 GHz, the worst case return loss, insertion loss, and isolation are 14.5, 1.89, and 20.5 dB, respectively, for the reflective shunt switch, and 22.2, 2.33, and 22.5 dB, respectively, for the absorptive series/shunt switch. Both switches exhibit an IIP3 of about 28 dBm and dissipate no dc power. The performance of these switches are comparable to other CMOS switches found in triple well technologies, on non-standard substrates, using special device structures, or using extra dc biases

The Effects of Scaling and Bias Configuration on Operating-Voltage Constraints in SiGe HBTs for Mixed-Signal Circuits

This paper presents a comprehensive picture of operating-voltage constraints in SiGe heterojunction bipolar transistors, addressing breakdown-related issues as they relate to technology generation, bias configuration, and operating-current density. New definitions for breakdown voltage, adopted from standard measurements, are presented. Practical design implications and physical origins of breakdown are explored using calibrated 2-D simulations and quasi-3-D compact models. Device-level analysis of ac instabilities and power performance, which is relevant to mixed-signal circuit design, is presented, and implications of the relaxed voltage constraints for common-base operation are explored.

A Monolithic 5-Bit SiGe BiCMOS Receiver for X-Band Phased-Array Radar Systems

This work presents a 5-bit receiver for X-band phased-array radar applications based on a commercially-available silicon-germanium (SiGe) BiCMOS technology. The receiver achieves a gain of 11 dB, an operational bandwidth from 8.0 to 10.7 GHz, an average noise figure of 4.1 dB, and an input-referred third-order intercept point (IIP3) of-13 dBm, while only dissipating 33 mW of power. The receiver also provides 32 distinct phase states from 0 to 360deg, with an rms phase error < 9deg. This level of circuit performance and integration capability demonstrates the benefits of SiGe BiCMOS technology for emerging radar applications, making it an excellent candidate for integrated X-band phased-array radar transmit/receive modules.

A Monolithic 24 GHz, 20 dBm, 14% PAE SiGe HBT Power Amplifier

A monolithic 24 GHz SiGe HBT power amplifier (PA), with an output 1 dB compression point of 20 dBm, is presented. The circuit is biased from a 5.1 V supply in a class AB mode of operation, resulting in a power added efficiency (PAE) of 14 % at the 1 dB compression point. The SiGe PA has a small-signal gain of 12 dB at 24 GHz, and a return loss of 9.6 dB and 16 dB at the input and output ports, respectively. This SiGe PA leverages the increased voltage swing capabilities associated with the common-emitter / common-base configuration for SiGe HBTs incorporated in a cascode architecture

An X-Band SiGe Single-MMIC Transmit / Receive Module for Radar Applications

The development of a single-MMIC transmit/receive (T/R) module for radar applications is described. The T/R module is fabricated in the IBM 8HP SiGe BiCMOS process technology. The topology of the T/R module is described. The performance of the underlying RF components is shown, including LNA, SP2T switches, SP3T switches, phase shifters, and power amplifiers, all with simulated and measured performance results. The simulated performance of the complete T/R module is presented, as well as the MMIC layout. The applicability to various radar systems and concepts is discussed. It is shown that the RF performance and the low power consumption of the device make it attractive for the described applications.