Active, frequency-selective meta-surfaces for reduced antenna footprint and jamming mitigation

ABSTRACT: Significant cost reductions and system improvements would ensue if multiple transmit and receive antennas could share one RF aperture without performance degradation due to self-interference phenomenon. Effects of radar jamming signals would be also be reduced through the use of a properly designed free space RF electromagnetic filter placed within that common aperture. To enable such improvements, a narrow band meta-surface, capable of dynamically switching between at least two, but possibly more, RF transmissive states is proposed. Utilizing a suitably designed electrical or optical element placed across the gap of a split ring resonator, external means can be used to short the gap, effectively switching between a split ring resonator structure and a donut shaped resonant cavity, each centered at a different, non-overlapping, resonant frequency. Already demonstrated at long-wave IR optical frequencies using numerical techniques, this effort extends this previous work to RF frequencies and explores, initially through simulation and in later phases through direct fabrication and characterization of the meta-surface, the design space need to selectively switch between 20, 44 and 60GHz. Resonant cavity geometry will be investigated as well as array effects associated with transmission bandwidth, center frequency, switching speed and overall fabrication complexity. BENEFIT: An active frequency selective surface will allow multiple transmit and receive antennas to share a common aperture, dramatically reducing system footprint and mitigating effects of jamming signals. Such a surface will find use in space-based platforms where communication and sensor payload size, weight and component count are of extreme importance.