Wideband Antenna Design for Time Domain RFI Measurements

This paper presents the design of a wideband antenna that will be used for time domain RFI measurements in the SKA radio telescope project context. The time required for the RFI qualification of equipment used on a radio telescope site can be reduced by performing the qualification measurements in the time domain. A wideband antenna that can handle pulsed time domain signals is needed to allow this. The Vivaldi antenna is a frequency-independent antenna widely used in Ultra Wideband (UWB) applications and is here adapted for a lower frequency band. It is investigated in simulation for time-domain use by measuring the time signal transmitted by the antenna. Simulations of the design show that an impedance bandwidth from 57 MHz to beyond 6 GHz is achieved and that time domain pulses are transmitted and received with limited distortion, which is confirmed by an improved high fidelity factor compared to the LPDA currently in use for RFI qualification measurements.