Study on relativistic Cherenkov source with metallic photonic band-gap structure

A Ka-band slow-wave structure consists of a two-dimensional metallic photonic band-gap and a slow-wave plate as its periodic unit. The photonic band-gap (PBG) structure, whose front view is shown in Fig.1, has a defect in the central of the triangular lattices. In metallic band gap, the first band gap begins from the zero frequency, which makes the TM₀₁-like mode always appear in defect, so the appropriate parameters can be designed to suppress all the higher-order TM_0n-like ( n ges 2 ) modes [1,2]. The parameters of photonic band-gap and the slow-wave structure are shown in Table I.