Proceedings of the 39th European Microwave Conference A Mixed-Signal X-Band SiGe Multi-Function Control MMIC for Phased Array Radar Applications D. Carosi, A. Bettidi, A. Nanni, L. Marescialli and A. Cetronio SELEX Sistemi Integrati S.p.A., Via Tiburtina Km. 12,400, 00131 Rome, Italy
[email protected] I. INTRODUCTION Phased array systems have been used for defence and commercial applications to achieve electronic beam control and fast beam scanning [1]. The performance of phased array systems is mainly affected by the performance of the transmit/receive modules (TRM) composing the array and in particular the MMIC chip-set which comprises, driver, high power and low-noise amplifier MMICs and a multi-function control MMIC, in the TRM “front-end”. At X-band frequency several multi-function control MMICs, also known as “core chips”, have been implemented using GaAs technologies [2–4]. With recent advances in Si-based technologies, low cost, high performance X-band core-chips can now be implemented, integrating several functions and allowing a dramatic reduction of chip size and cost. Although silicon technology does not outperform GaAs when classic microwave parameters are compared, cost is a clear benefit in the performance/cost “trade-off” for choosing such a technology. Furthermore the SiGe core-chip solution can be viewed as the first milestone of a roadmap leading to digital TRM ”back-end” solutions and indeed complete mixed-signal system on-chip solutions for moderately low power TRM applications. In this paper the design, fabrication and RF performance of a silicon based multi-function core-chip will be presented by outlining the architecture and technology used, illustrating the simulated results of the core-chip and related sub-blocks and finally reporting the achieved RF performance(s). 978-2-87487-011-8 © 2009 EuMA II. CORE-CHIP ARCHITECTURE AND TECHNOLOGY In Fig. 1 is illustrated the block diagram of the SiGe mixedsignal X-Band multi-function control MMIC. As shown said component comprises: SPDT switches, gain amplifiers, 5-bit phase shifter and 5-bit attenuator and digital to parallel converter. Integrating the latter function on-chip implies a substantial reduction in the number of control lines and this, from a TRM point of view, results in less bonding wires, no need of off-chip level converters or inverters and reduced number of pins of the control ASIC. In particular for said component only six control lines are needed to set a 5-bit phase shifter, 5-bit attenuator and input and output T/R switches, with the capability to store two command words. RX IN AMP PHS AMP φ AMP φ PHS RX O