An X-Band Slow-Wave T/R Switch in 0.25-$\mu\hbox{m}$ SiGe BiCMOS

Abstract

This brief presents a fully integrated X-band transmit/receive (T/R) switch using slow-wave transmission lines for X-band phased-array radar applications. The T/R switch was fabricated in a 0.25- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\mu\hbox{m}$</tex></formula> SiGe bipolar CMOS (BiCMOS) process and occupies 0.73- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{mm}^{2}$</tex></formula> chip area, excluding pads. The switch is based on shunt–shunt topology and employs isolated n-channel (NMOS) transistors and slow-wave microstrip lines. Additionally, resistive body floating and dc biasing are employed to improve the power-handling capability <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({P}_{1\, {\rm dB}})$</tex></formula> of the switch. The T/R switch resulted in a measured insertion loss of 2.1–2.9 dB and isolation of 39–42 dB from 8 to 12 GHz. The input referred <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${P}_{1\, {\rm dB}}$</tex></formula> is 27.6 dBm at 10 GHz. To our knowledge, this brief presents the utilization of slow-wave transmission lines in T/R switches for the first time. Furthermore, it can simultaneously satisfy stringent isolation, insertion loss, and power-handling capability requirements for implementing a fully integrated SiGe T/R module.