A compact waveguide diplexer employing dual-band resonators

This paper outlines a new class of diplexers realized using a combination of dual-band cavities and single-band cavities. The proposed diplexer does not require junctions and can achieve similar performance with fewer cavities, thus significantly reducing the size of the diplexer when compared to traditional approaches. The concept is potentially applicable to most dual-band cavities as demonstrated in this paper using rectangular waveguide cavities. A unique layout is proposed that combines the use of dual-band cavities operating in TE₁₀₁ and TE₀₁₁ modes as well as single-band cavities operating in TE₁₀₁ or TE₁₀₂ mode. The result is a diplexer that is very compact in size while offering increased Q and an improved spurious free window. To verify the concept a 4^th order Ku-band diplexer is designed, manufactured, and tested to allow comparison to a traditional design.