In this paper, the design of a miniature antenna dedicated to the detection of airliners through the demodulation of Automatic Dependence Surveillance-Broadcast system (ADS-B) signals is presented. This antenna is designed for being embedded on the top of a drone in order to detect and avoid collisions with airliners. This antenna consists of an array of Planar Inverted-F Antennas, a quadrature feed network (FN) and a reflector plane (RP). The FN is designed to have output signals with the same amplitude and a 90° phase difference between each other. It achieves circular polarization and maintains the axial ratio of the antenna under −3 dB at the desired frequency (1.09 GHz). The antenna with the FN was manufactured and characterized. It weighs approximately 145 kg with its RP. The measured gain of the proposed antenna is about +3.7 dBi. To validate the design, the manufactured antenna was tested with a Universal Software Radio Peripheral for the processing of ADS-B signals at the French National Microwaves Days 2019 (JNM) student contest. The detection of airliners can reach up to 437 km.

A tunable radiator for space application has been developed to meet stringent requirements in terms of electrical and environmental specifications but also low mass, simple manufacturing and low cost. The element is based on the folded planar inverted F-antenna, with size of one quarter of wavelength. It is mechanically tunable to adjust input impedance for any various positions on the satellite body and possible obstacles and protrusions. Results in terms of radiation pattern, S parameters, shock and vibration tests are presented. The antenna operates in ultra-high frequency band (400 MHz) in linear polarization. It has been designed to act as the basic element for miniaturized multi-function antenna systems on board of small satellites that can operate in three different radiating modes and in both left and right hand circular polarizations.