Abstract—A Miniaturized high temperature
superconducting filter applied to mobile communication is
designed based on a novel double-folded microstrip hairpin
resonator which can be used to adjust the intensity of
electromagnetic coupling. The filter has the characteristics of
small size and a pair of transmission zeros to improve
out-of-band suppression without cross coupling. According to
the theory of complex electromagnetic coupling, the circuit
structure of the double folded microstrip hairpin resonator is
analyzed. By adjusting the lengths of different circuit parts of
the microstrip resonator, the exchange of electromagnetic
coupling characteristics can be realized, thus introducing
transmission zeros. At the same time, the mutual cancellation
of electromagnetic coupling can reduce the distance between
resonators, so the overall size of the filter is reduced. A double
transmission zeros miniaturized microstrip HTS 11-order filter
with the center frequency of 1300MHz and bandwidth of
200MHz without cross-coupling is designed. The measured
indexes of the filter at 77 K: the center frequency is 1300 MHz,
3 dB relative bandwidth is 15%, in-band insertion loss is less
than 0.25 dB, the size is 24.81 mm 11.60 mm
(0.26λgc 0.12λgc), and out-of-band rejection is more than
70dB. The overall size test results are consistent with the
simulation results.
Index Terms—High temperature superconductivity (HTS),
filter, transmission zeros, cross coupling.
Liguo Zhou, Yanshuang Han, Hang Wu, Hui Li and Tianliang Zhang
are with the School of Aeronautics and Astronautics, University of
Electronic Science and Technology of China, Chengdu 611731, China
Zhihe Long is the Department of Mechanical Engineering, City
University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
(e-mail: zhouliguo0710@163.com).
[PDF]
Cite: Liguo Zhou, Yanshuang Han, Hang Wu, Zhihe Long, Hui Li, and Tianliang Zhang, "Multi-order Miniaturized Dual Transmission Zeros HTS Filter without Cross Coupling," International Journal of Information and Electronics Engineering vol. 10, no. 2, pp. 28-34, 2020.
