Wideband Measurement in a Small Shielded Box Using Equiangular Spiral Antennas

Abstract

Small shielded boxes are nowadays widely used for measurement of EMS, EMI and sensitivity properties of different devices. This paper deals with an improvement of commercial small shielded box parameters for a measurement of sensitivity of small mobile devices in 650 MHz to 4 GHz frequency band. Optimization of shielded box parameters is obtained by an inner area modification. Suitable wideband equiangular spiral antenna was designed for this measurement. Parameters of antenna inside the box, such as gain, impedance, directivity etc. are discussed in the paper. Effects of antenna positions in the box for a transmission are shown and the best configuration of antennas placing for the transmission in the shielded box is chosen.