VHF Discrete-Tuned Filters With Constant Insertion Loss and Absolute Bandwidth
- Resource Type
- Conference
- Authors
- Zhao, Zhi-Yuan; Kang, Guo-qin
- Source
- 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) Microwave and Millimeter Wave Technology (ICMMT), 2019 International Conference on. :1-3 May, 2019
- Subject
- Components, Circuits, Devices and Systems
Fields, Waves and Electromagnetics
- Language
These instructions give you basic guidelines for preparing papers for conference proceedings. This letter presents a novel two-pole tunable bandpass filter with constant insertion loss and absolute bandwidth designed for 30-90 MHz operation. The centre frequency and inter-stage coupling are synchronously discrete-tuned by connecting PIN switched capacitor banks at the terminal ends of the helical inductors. LC parallel circuits without tuning are chosen as the input/output impedance matching, which meet the external quality of constant absolute bandwidth. The experimental filter has an almost constant insertion loss between 2.95-3.5 dB with 3-dB absolute bandwidth of $2.3 \pm 0.3\ \text{MHz}$. The shape factor (BW 30-dB / BW 3-dB ) is smaller than 5.6 and $\text{IIP}_{3} > 29.5\text{dBm}$ over the tuning range. The measured results show good agreement with the simulated ones.