Design of Varactor-Loaded Transmission-Line Phase Shifter with Integrated Single-Stage LNA in 0.18 um RF CMOS Technology

This paper presents a 2.4 - 2.48 GHz varactor-loaded transmission-line (VLTL) phase shifter used for beamforming in indoor positioning systems (IPS). The phase shifter consists of two main blocks integrated on the same substrate: a single-stage Low-noise amplifier (LNA) block and a 56 cascading low-pass networks block. A control voltage of 4 - 24 V is applied to both of these blocks for operation. The simulated results provide a continuous phase shift range of around 300 degrees with an average gain of 8.9 ± 0.4 dB. Moreover, the noise figure (NF) is maintained lower than 2.8 dB while the reflection coefficient at the input and output of the circuit yields below -15 dB. The design is implemented on 0.18 um RF CMOS technology with a core size of 4.4 mm x 3.4 mm.