TABLE OF CONTENTS This chapter has been concerned with the design of waveguide filters to realise various transfer functions. Initially a review of the basic theory of rectangular and circular waveguides and waveguide resonators is presented. Next a design procedure for waveguide bandpass filters with all-pole transfer functions is developed, and supported with an example. More complex transfer functions require either cross-coupled or extracted pole filters. The former enable realisation of transfer functions with real-axis transmission zeros, i.e. prototypes with all positive couplings. The development of design procedures for these generalised waveguide filters is presented. The restriction of transmission zero locations in the real axis is removed by the use of extracted pole waveguide filters, the design theory of which is developed and again supported by an example. Finally techniques for the design of dual-mode filters are presented. It is important to note that the extracted pole and dual-mode techniques are relevant to the dielectric resonator filters described in the next chapter.
