Quasi-Isotropic Reconfigurable Antenna through Complementary Radiation Patterns for Wireless Capsule Endoscope

Abstract

A radiation pattern reconfigurable antenna, operating at the Industrial, Scientific, and Medical (ISM) band (902–928 MHz), is investigated for wireless capsule endoscope (WCE) systems. The proposed antenna is composed of a planar inverted-F antenna and two conformal branches. By controlling PIN diodes on the conformal branches, the antenna can switch between different working states, corresponding to two complementary radiation patterns. The simulated −10-dB impedance bandwidth in each state is 7.6% (880–950 MHz). Simulation results show that the antenna has a quasi-isotropic radiation pattern after reconfiguration with a gain deviation of 4.5 dBi in the 360° full space.