A Programmable Microwave Components Reconfigurable Between Four Functions

Abstract

Aiming at realizing a reconfigurable microwave passive component programmable by software, whose counterpart in the digital domain is an FPGA, this work proposes a novel programmable passive microwave component. The component consists of basic functional units, transmission units and microwave switches, denoted as the basic building blocks. The states of the switches are controlled by software, resulting in different combination of the building blocks in different topologies where the distribution of the electromagnetic (EM) field is altered, thus different functions of the component. More specifically, the design is based on a planar micro-strip (MS) patch circuit. A resonance patch, a slot, a coupling MS line are used as the basic functional units, impedance transformation and MS transmission lines are used as the basic transmission units, which are connected by microwave PIN diode switches to form different topologies that can work as an antenna, a filter, a splitter, or a coupler with an FPGA acting as the control circuit. A prototype component is fabricated and measured with the following results. The antenna central frequency is 3.22 GHz, with realized gain 6.2dBi. The pass-band of the filter is 3.35-3.53 GHz (a fractional bandwidth of 6.3%) with an insertion loss (IL) ~ 2.7 dB. The splitter has a working band of 2.4-3.5GHz, a 1.6dB IL, a ±0.4dB amplitude unbalance and a ±3.4° phase unbalance. The coupler works at 2.5-5 GHz, whose IL~1.7dB, coupling coefficient ~30±1.4dB. The four functions can be switched at will among each other by software control.