Niklas Billstrom

An AlGaN/GaN HEMT-Based Microstrip MMIC Process for Advanced Transceiver Design

A MMIC process in AlGaN/GaN technology for advanced transceiver design has been developed. The process is based on microstrip technology with a complete model library of passive elements and AlGaN/GaN HEMTs. The transistor technology in this process is suitable for both power and low noise design, demonstrated with a power density of 5 W/mm, and an NFmin of 1.4 dB at X-band. Process stability of subcircuits, complementary to power amplifiers and LNAs, in a transceiver system have been investigated. The results indicate that an all AlGaN/GaN MMIC transceiver is realizable using this technology.

An X-Band AlGaN/GaN MMIC Receiver Front-End

This letter presents an integrated AlGaN/GaN X-band receiver front-end. This is to the authors knowledge the first published results of an integrated AlGaN/GaN MMIC receiver front-end. The receiver uses an integrated SPDT switch to reduce size, weight and cost compared to circulator based transceiver front-ends. The integrated front-end has more than 13 dB of gain and a noise figure of 3.5 dB at 11 GHz.

An SiC MESFET-Based MMIC Process

A monolithic microwave integrated circuit (MMIC) process based on an in-house SiC MESFET technology has been developed. The process uses microstrip technology, and a complete set of passive components, including MIM capacitors, spiral inductors, thin-film resistors, and via-holes, has been developed. The potential of the process is demonstrated by an 8-W power amplifier at 3 GHz, a high-linearity S-band mixer showing a third-order intercept point of 38 dBm, and a high-power limiter

Impact of Trapping Effects on the Recovery Time of GaN Based Low Noise Amplifiers

This study investigates recovery time of the gain of AlGaN/GaN HEMT based low noise amplifiers (LNA) after an input overdrive pulse. Three LNAs, fabricated in two commercial MMIC processes and a Chalmers in-house process, are evaluated. The Chalmers process has an unintentionally doped buffer instead of the intentional Fe doping of the buffer which is standard in commercial GaN HEMT technologies. It is shown that the LNAs from the two commercial processes experience a severe drop in gain after input overdrive pulses higher than 28 dBm, recovering over a duration of around 20 ms. In contrast the LNA fabricated in-house at Chalmers experienced no visible effects up to an input power of 33 dBm. These results have impact for radar and electronic warfare receivers, which need to be operational immediately after an overdrive pulse. The long time constants suggest that these effects are due to trapping in the transistors with the Fe doped buffer playing an important role.

Compact tile module for S-band AESA radar systems

This paper presents the design and verification of an S-band receiver module for a 2D AESA array. The design includes an S-band chipset and a compact LTCC module using a tile architecture. Even if the primary goal was a system demonstrator, great emphasis was put in achieving a low cost and high manufacturability module concept. The methodology and concept was proved by successful production and fully testing of 120 modules within two weeks.

UTSi® CMOS tunable RF front-end filters and LNAs for wide-band phased array antennas

We have studied the possibility to realize tunable RF front-end filters and LNAs for wide-band phased arrays using a 0.25 mum UTSireg (ultra thin silicon) CMOS low cost technology. Measured results of an X-band passive filter-bank and a C-band active tunable filter show that adequate performance can be obtained (in terms of relatively low losses or high gain and out-of-band rejection over wide tuning ranges) while using small circuit areas. The UTSireg CMOS based RF components we present in this paper could contribute to the miniaturization and integration of RF front-ends in phased arrays.

A GaAs MMIC chipset in SMT packages for a wide band ESM system

A highly integrated multifunction GaAs MMIC chipset intended for wide band signal detection in the C-, X-, and Ku-band has been developed and verified. The chipset consists of three chips with amplification, frequency conversion, gain-control, and signal distribution within the frequency range 2-25 GHz. The chipset enables sub-band selection within 5-18 GHz and consecutive transformation into a lower frequency band of 2-5 GHz, including out of sub-band filtering. The transformation of frequency band is solved by signal mixing in two steps, filtering the signal in-between. The first mixer is based on a single balanced resistive FET mixer in order to improve suppression of unwanted IM-products, while the second mixer is a single FET mixer, optimizing for a small circuit layout. For the in-between filtering, a semi-lumped filter design is chosen. To reduce production costs all chips are mounted in packages to enable surface mount techniques (SMT). The chipset is intended for integration in a low cost wide band electronic support measure (ESM) system.

Compact receiver module for X-band radar applications

This paper presents, the design, realization and measured results of a highly integrated Multi-Chip-module (MCM) developed for X-band radar applications. The MCM is built up in a LTCC substrate. Embedded within the substrate is a bandpass stripline filter. The main functionality is realized by two multi-function MMIC. The MCM is an integral part of a future multi-channel AESA radar system.