Substrate integrated waveguide multiband bandpass filter design

Microwave filters are frequently used components in RF/Microwave systems and ensure that only desired frequencies of electromagnetic signals are transmitted. There are various kind of filters according to their frequency responses (lowpass, highpass, bandpass and band stop filters) and different structural features (microstrip, cavity, lumped element, ceramic and waveguide filters). Substrate Integrated Waveguide (SIW) filters which are designed using successive vias on a substrate whose both surfaces are plated with conductive metals are also frequently used filter type in microwave systems. Substrate Integrated Waveguide filters could be compared with dielectric filled waveguide filters. However, Substrate Integrated Waveguide filters have advantages over waveguide filters in terms of production, size and weight. In addition, Substrate Integrated Waveguide filters could be also preferred because frequency responses of this kind of filters are converges to frequency responses waveguide filters. With the developing technology like 5G/6G and Internet of Things, faster communication systems are needed nowadays. Therefore, multiband wireless systems and apparatus are need to be developed. Multiband bandpass filters are raised because of that reason. In this thesis, Substrate Integrated Waveguide filter designs in K frequency band are aimed. For that purpose, single channel SIW bandpass filters are designed in the light of theoretical information. The designed channel filters are simulated on a three-dimensional electromagnetic solver, and the frequency responses of the channel filters are optimized. After that, channel filters are implemented to each other to design multiband bandpass filters. In this direction, a diplexer design is carried out, and its frequency response is examined. In addition to that, a triplexer is designed. After electromagnetic simulations and optimizations, SIW multiband bandpass filters are produced, and the measurement results are evaluated.