Review on Substrate Integrated Suspended Line Based Filters with Stub Loaded Hexagonal Shaped Low Pass Filter

A multilayered realization of circuits using embedded cavities is done in substrate integrated suspended line (SISL) technology. With the emerging developments in the RF and Microwave communication systems, the role of filters is very important. As most of the frequency bands are currently in use for various applications, it is important to select the exact frequency of design and cut off the undesired band from the circuit. This paper presents a review on the SISL based filters and their performance comparison. A compact elliptical LPF is proposed based on SISL whose performance is enhanced by including open shunt stubs. Introduction of three stubs symmetrically on either side of the filter resulted in extra three transmission zeros in the S21 response. The filter realizes a pass band from 0-2.6 GHz with the perfect rejection and roll off of 180dB/GHz.