HTS narrowband stripline filter at 2.1 GHz with high power handling capability

Abstract

with the predicted ones in both amplitude and phase. Simulated and measured return losses are higher than 10 dB over the frequency range of 1.9 -3.2 GHz, showing a fractional bandwidth of ϳ50%. Meanwhile, the measured phase imbalance varies in a range of 179°-215°over the above operating range as can be seen in Figure 3. It needs to be highlighted here with reference to Figure 4 that as the two patches are properly unequalized, the amplitude imbalance less than 1.0 dB now achieves a wide frequency range of 2.0 -3.8 GHz. CONCLUSIONA planar vialess balun is proposed on a basis of three multisecion /4 uncoupled/coupled lines. By implementing a wide backside aperture and two unequal patches underneath the coupled microstrip line, the constituted balun with miaturized size achieves good amplitude/phase balances and input impedance matching over a wide frequency range of 1.9 -3.2 GHz. The predicted attractive performances are validated by experiment.

Progress on applications of high temperature superconducting microwave filters

“…In recent years, many works have concentrated on improving the power handling capabilities of HTS filters by using various types of resonators, such as bulk resonators [26][27][28], dual-mode resonators [29][30][31], strip line resonators [32][33][34][35][36], and microstrip line resonators [37][38][39][40][41][42][43][44], and impressive progress has been made. Generally, the critical current of the HTS bulk resonators and strip line resonators can be significantly larger than that of the microstrip resonators.…”

A high temperature superconducting group‐delay equalizer

“…Firstly, it is much smaller in size as it is the planar structure; secondly, it has very small insertion loss because the surface resistance of HTS thin films is much lower than that of traditional metals in microwave band [3]. Hence, it is more applicable, especially, for equalizing the HTS filters [4,5].…”