This paper presents a four-pole superconducting filter with an ultra-narrow bandwidth of only 440 kHz at 220 MHz. A pair of symmetrical transmission zeros is introduced to improve the steepness of the bandedges. The filter circuit is realized on YBCO/MgO with an area of 36.6 mm×12.4 mm. The measured results show a high performance and are in good agreement with the simulations. The minimum insertion loss is 0.42 dB, the return loss is better than 15 dB, and the out-of-band rejection is better than 60 dB.

In this paper, the analogue of electromagnetically induced transparency is achieved in a magnetic metamaterial consisting of coupled “radiative” square closed loop (SCL) and “dark” square spiral resonator (SSR). Full-wave numerical simulations are carried out to validate the EIT-like effect of the magnetic metamaterial. Transmission spectrums and surface current distributions for the metamaterial are presented. It is shown that placing the SSR close to the SCL causes the electromagnetic field energy to be coupled back and forth between them. This leads to destructive interference and the transparency window in the transmission stop-band of the metamaterial. In addition, it is numerically demonstrated that the magnetic metamaterial can be employed as a refractive-index based sensor with a sensitivity of 41.3 mm/RIU, which means that the resonance wavelength of the sensor shifts 41.3 mm per unit change of refractive-index of the surrounding medium.

In this paper, a novel approach is presented to calculate the lumped parameters of right/left-handed Structures. By this method, the equivalent circuit can be extracted, and the left/right handed features can be certified. Furthermore, the propagation constant of periodic structures can fit well with simulation and measurement.

In this literature, a novel left-handed circularly polarized voltage-controlled leaky wave antenna is presented with a scanning range of 0°to -37°with a perfect axial ratio at the most time below 2 dB. The structure depends on CRLH (Composite Right/Left Handed) transmission line with a cross finger coupled line added, which gives additional performance on the farfield axial ratio. Also the principle of the structure is discussed and an equivalent circuit is presented for further study.