In this paper, the research advances in SIW-like (Substrate Integrated Waveguide-like) guided wave structures and their applications in the State Key Laboratory of Millimeter Waves of China is reviewed. Our work is concerned with the investigations on the propagation characteristics of SIW, half-mode SIW (HMSIW) and the folded HMSIW (FHMSIW) as well as their applications in microwave and millimeter wave filters, diplexers, directional couplers, power dividers, antennas, power combiners, phase shifters and mixers etc. Selected results are presented to show the interesting features and advantages of those new techniques.

We address, in this paper, the main features of hybrid modes propagating in a rectangular waveguide partially filled with pseudochiral Ω-slabs. For the particular case of a uniaxial Ω-slab, we show that LSE and LSM hybrid modes can propagate in this inhomogeneously filled rectangular waveguide. The influence of the Ω-parameter, which characterizes the magnetoelectric tensors of the bianisotropic slab, on LSM modes is analyzed--namely an increase in the bandwidth for monomodal operation is reported. In addition, a field displacement effect and a variable phase shift proportional to the change of the Ω-parameter are attained. Finally, it is shown that the propagation characteristics are independent of the direction of propagation and so, unlike the case of magnetically biased ferrite loading, reciprocal devices can be achieved.

This paper describes the properties of non-dispersive and dispersive delay lines fabricated using EuBaCuO superconducting films. The 24 cm long stripline non-dispersive delay line showed a very low loss of 0.3 dB/nsec at 77 K and 10 GHz, and no dispersion at a delay time of 2.3 nsec at frequencies below 20 GHz. The 14 cm long microstrip dispersive delay line with modal dispersion exhibited a relative delay time of approximately 120 psec in the 118 GHz frequency range. The 26 cm long stripline dispersive delay line with structural dispersion due to coupling provided a relative delay time of 230 psec in the above frequency range and roughly the same loss as a non-dispersive delay line.