Compact, Microstrip-Based Folded-Shorted Patches: PCB antennas for use on microsatellites

A compact printed circuit board (PCB) antenna for use on microsatellites was designed and measured for ultrahigh-frequency (UHF) low-data-rate communication applications. The miniaturized and fully integrated antenna structure consists of an array of four linearly polarized folded-shorted-patch elements placed in a sequential rotation with a coupler-based feeding circuit to achieve circular polarization (CP). The dimensions of the fabricated and measured PCB antenna are 0.2λ⁰ x 0.2λ⁰ x 0.05λ⁰. The measured gain values are greater than 0.4 dBiC at 398 MHz. A design procedure for the microstrip-based antenna is provided along with a transmission line model that accurately predicts the operation and resonant frequency of the miniaturized patches. Numerical calculations agree with the full-wave simulations as well as the antenna measurements, which demonstrate functionality. The miniaturized, low-cost antenna unit can be useful for space communications and other surveillance applications as well as network formations of small satellites where broad-beam patterns with low gain values are required for adequate coverage.