An X-Band Expandable Reconfigurable 1:2 Power Divider Switch for Switched Beam-Forming Networks in 0.10-µm GaAs Process

In this letter, an X-band expandable reconfigurable 1:2 power divider switch (PDSW) is proposed for switched beam-forming networks. A switched inductor-artificial transmission line (SI-ATL) is proposed. With proper switch logic, the SI-ATL features two types of transmission line (TL): 1) a $\lambda $ /4 TL of $50\sqrt {2} \; \Omega $ and 2) a TL of $50 \; \Omega $ . This enables the PDSW to realize three port states of two corresponding modes, including single-pole–double-throw (SPDT) mode and power divider (PD) mode. The PDSW has the ability to be expanded to an N-stage 1: $2^{N}$ matrix with $2^{2^{N}} - 1$ states. The proposed design is fabricated with a 0.10- $\mu $ m GaAs pHEMT process. The measurement results show a $\leq 1$ .2-dB insertion loss (IL), a $\geq $ 10-dB return loss (RL), and a $\geq 40$ -dBm input 3rd-order intercept points (IIP3), in both modes. The isolation is 27–32 dB for SPDT mode and 14–31 dB for PD mode.

I. Introduction

Beam-forming is widely used in modern radar and wireless communication systems. One of its essential techniques is to reconfigure the antenna array using reconfigurable feed networks [1], [2]. For such systems, single-port excitation (SPE) mode is defined as the common port connected with one output port (e.g., single-pole–multithrow (SPMT) switch); multiport excitation (MPE) mode is defined as the common port connected with multiple output ports [e.g., power divider (PD)]. The beam directions are determined by the number of SPE modes and the number of MPE modes together. Therefore, combining the functions of SPMT and PD, and expanding the number of excitation states, have great significance for beam-forming systems.