RECONFIGURABLE ANTENNA STRUCTURES USING MEMS TECHNOLOGY
E. ERDIL, S. ONAT, K. TOPALLI, I. ISTANBULLUOGLU, M. UNLU, S. DEMIR, L. ALATAN, O. AYDIN CIVI, S. KOC, T. AKIN

Introduction
The tunable and reconfigurable properties of RF MEMS components have been investigated in various studies on switches, capacitors, inductors, resonators, filters, phase shifters, and matching networks [1]. These properties of RF MEMS components can be used as an enabling tool in wireless communication and radar systems.
The integration of tunable RF MEMS components with radiators is one of the examples to the usage of this enabling technology resulting as reconfigurable antennas in terms resonant frequency, polarization, radiation pattern.
This paper presents two reconfigurable antenna structures using MEMS technology. The first structure is a CPW-fed rectangular slot antenna where a short circuited stub loaded with MEMS capacitors is inserted to the antenna structure. The variable capacitors, which are controlled with DC voltage, are placed onto the stub in order to achieve a control on the characteristic impedance of the loading stub.
Since the characteristic impedance of the stub has an effect on the resonant frequencies, the resulting antenna has reconfigurability on the resonant frequencies of the antenna. The other structure is an inset fed microstrip patch antenna with a slot opening which is used to obtain a dual frequency antenna. The switches placed on the inset feeding provide matching for each of the dual frequencies depending on the states of the switches controlled with DC actuation.