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Abstract-Low-Loss resonators with high Q factor have special importance in modern microwave telecommunications systems. In this paper, a modern dual-band CSRR with high Q factor is first examined using SIW technology on a surface waveguide. It should be noted that the proposed structure paves suitable way for emitting and propagating wave in two passing bands (approx. 4.7 and 5.3 GHz) below cutoff frequency waveguide. High Q factor and its high small-sized percentage is the salient specification of this structure as compared to other similar planar resonators proposed in various references.At the end of this paper, three applications of this resonator are studied in designing a small multiband filter with high Q factor, a small multi-band diplexer with low passage bandwidth and a planar oscillator with low-phase noise. According to the scientific literature, the proposed oscillator was found to enjoy the best performance at low phase noise for planar microwave oscillators.

Two new designs of compact microstrip antennas, where metamaterials are placed on structure as superstrate, are proposed. The newly designed metamaterial unit cell and antenna feed position optimized by particle swarm optimization. It was found that the characteristics of novel microstrip antennas with designed metamaterials placed on the superstrate are comparable to the conventional patch antennas, while their gain, directivity and radiating efficiency are noticeably improved. Gain of microstrip antenna is increased 3dB to 4dB and level of back lobe is decresed.

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