具有宽阻带特性的6阶自均衡高温超导滤波器

6-order self-equalization high temperature superconducting filter with wide stopband characteristics

本文提出了一种新颖的L型阶跃阻抗谐振器,该谐振器具有结构紧凑、抑制二次谐波能力强及易于实现电耦合及磁耦合等特点。使用该谐振器设计并制作了一款具有小型化、高选择性及宽阻带特性的6阶自均衡高温超导滤波器。测试结果表明,在70 K温度下滤波器的中心频率为1 601 MHz,3 dB带宽为24 MHz,带内回波损耗<14.87 dB,带内最大插入损耗约为0.22 dB,60%带宽范围内群时延起伏<3.13 ns,通带两侧具有一对深度的传输零点,实现了1 632~5 511 MHz范围内衰减>60 dB的宽平坦阻带。

In this paper, a novel L-shaped step impedance resonator was proposed. The resonator has the characteristics of compact structure, superior to suppress second harmonic and easy to realize electric coupling and magnetic coupling. A 6-order self-equalization high temperature superconducting filter with miniaturization, high selectivity and wide stopband characteristics was designed and fabricated using the resonator. Measurement at 70 K shows the physical HTS filter has a center frequency of 1 601 MHz, 3 dB bandwidth of 24 MHz, the return loss is less than 14.87 dB, the maximum insertion loss is about 0.22 dB, and the group delay fluctuation is less than 3.13 ns within 60% of the bandwidth, there is a pair of deep transmission zeros on both sides of the filter passband, the second harmonic is pushed to 3.5 times beyond the fundamental frequency, and a wide flat upper stopband with more than 60 dB attenuation in the range of 1 632 MHz to 5 511 MHz is achieved.