Dual-band FSS design using LC traps

Abstract

This paper introduces resonant "traps" and their potential uses to frequency selective surfaces (FSS). A trap can be considered a passive frequency selective switch offering a high or low impedance state depending upon operating frequency. The paper illustrates an established trap application and introduces the potential for use in FSS designs. A harmonically or near harmonically related dual-band annular ring application is discussed, with the design being realised both by simulation and measurement, the results of which are presented and evaluated.

Utilizing everyday metallic structures as UHF RFID antennas

“…This negates the need to break the conductor. The resonator is designed with (1)- (4), where r is the turns ratio, k the coupling factor and y = LC. Practical values are k = 0.2-0.5, r = 1.0-1.3.…”

“…The dipole would be resonant at the lowest frequency of interest with trap pairs placed accordingly to achieve higher frequency resonances. Traps have also more recently been incorporated in frequency selective surfaces (FSS) [4][5][6] to provide dual-band, band-stop and band-pass operation. Although traps are effective they require physical breaks to be inserted in the conductor.…”

An Active Ring Slot With Rf Mems Switchable Radial Stubs for Reconfigurable Frequency Selective Surface Applications

“…Of these geometries, ring based designs have shown excellent performance in supporting various types of polarizations and have demonstrated a good insensibility with respect to the angle of incidence [35]. Various FSS and RFSS based on rings have been proposed, including shorted ring slots, loaded ring slots, active rings, split rings, and trapped rings [36][37][38][39]. Furthermore, ring slot FSSs have demonstrated low insertion loss and low cross-polarization levels [40].…”

A passively switched dual-band circular FSS slot array

“…Simultaneous dual and multi-band operation of band-stop FSSs is an established technique, either by the use of concentric elements, as in the case of loops or tuned traps [1]- [3]. Dual-band operation of slot type elements is typically not as convenient, particularly for concentric or nested element designs as the removal of conducting material to create additional slots can result in isolated sections of conductor and significantly detuning the surfaces' fundamental resonance.…”