Narrow-band Filters — Lesson 6

This lesson covers the principles of designing microwave and digital service filters, focusing on band stop and band pass filters. It explains the use of resonators, including shunt and series resonators, and their role in building narrowband filters. The lesson also discusses the limitations of using open stub gap coupled resonators in series and the advantages of using them in shunt. It provides a detailed explanation of how to calculate the insertion loss of a band pass filter and how to design a filter using given conditions. The lesson concludes with a discussion on the importance of connecting open or shorted stubs in shunt when used as a resonator.

Video Highlights

00:15 - Introduction and recap of previous lesson
03:17 - How to make a band stop filter using a resonator.
10:25 - Insertion loss of a band pass filter.
17:11 - Calculating the resonant frequency.
22:15 - How to design a filter using the given conditions
24:07 - Summary of the module and the key points to remember

Key Takeaways

- Shunt and series resonators can be used to build narrowband filters.
- Open stub gap coupled resonators can act as a series or shunt resonator depending on the frequency.
- The insertion loss of a band pass filter can be calculated using specific formulas.
- For band stop filters, a shunt resonator is used, while for band pass filters, a series resonator is used.
- The design of a filter involves calculating the loaded Q factor, finding the reactance, and determining the length of the intermediate section.