Miniaturised FSS structure with excellent angular stability based on strong coupling for millimetre‐wave communication

Abstract

A miniaturised low-profile frequency selective surface structure (FSSs) with highly angular stability is proposed in this Letter. Due to the strong coupling introduced by the thin dielectric, the designed FSS has a miniaturised unit size of 0.28λ, which can be applied to millimetre-wave communication. To better analyse the structure performance, the equivalent circuit model (ECM) is proposed. Moreover, the prototype with the centre working frequency of 30 GHz is fabricated and measured to verify the design. The insertion loss is demonstrated <0.12 dB with a bandwidth of 2.5 GHz under the normal incident wave. While the incident angle changes to 60°, it is <1.96 dB. In addition, the transmission zeroes remain at 36.4 GHz, when the incident angle varies from 0° to 60°, which result in a stable stopband following the passband. Particularly, the passband and stopband are controlled by two coupling capacitors, so the passband and stopband can be adjusted independently by changing the different parts of the structure. Finally, the results obtained by the ECM, simulation, and measurement have a good agreement, which demonstrates that the proposed FSS design is a good candidate for millimetre-wave communication.