A Software Controlled Polarization and Pattern Reconfigurable Microstrip Parasitic Array Antenna for a Market Mediated Software Defined Communications System

Abstract

Software Defined Radio (SDR) provides a platform for a reconfigurable communication system that is solely controlled by a software program with access to certain hardware modules. SDRs are typically connected to very minimalistic, and often, manually controlled reconfigurable antenna(s) with no software control over radiation parameters. Hence, on a wave propagation front, the radiator does not capitalize on the software infrastructure it is connected to. This thesis presents a software controlled pattern and polarization reconfigurable microstrip patch antenna, with reconfigurable parasitic elements, for reconfigurable wireless networks and applications.

The antenna is designed to operate from 2.4 GHz to 2.5 GHz, covering all channels (channels 1 through 14) of the 2.4 GHz ISM band. This broadband behavior is achieved with a two-layer stacked annular ring patch antenna, separated by a layer of foam. This antenna is dual probe-fed to achieve vertical and horizontal linear polarizations as well as right-hand and left-hand circular polarizations. Pattern reconfiguration is achieved with a third layer composed of microstrip patch elements acting as parasitic radiators, either reflecting or directing a beam in a direction, which are controlled by RF PIN diodes. Elements are placed such that pattern reconfiguration is possible across all polarization modes.

Various iterations of the design process are discussed along with their issues and solutions. Other reconfiguration techniques are also suggested as part of future work.