Dielectric Resonator-Based Evanescent-Mode Waveguide Filtering Antenna
Dristi Singhal, Kirti Dhwaj
Abstract
An inline configuration of a two-pole <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{TE}_{01\delta }$</tex-math></inline-formula> mode dielectric resonator-based evanescent-mode waveguide filtering antenna is presented. The proposed design ensures matching of complex admittance at small aperture of evanescent-mode open-ended waveguide (EMOEW) to real admittance of the generator across a 10 dB return-loss bandwidth of 3.7%. The EMOEW having cutoff frequency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{f}_{c}$</tex-math></inline-formula> = 9.6 GHz, radiates with an endfire realized gain of 4.5 dBi at operating frequency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$f_{0}$</tex-math></inline-formula> = 8.1 GHz. The presence of high-Q dielectric resonators provides sharp selectivity in filtering response, with a shape factor of 2.5 at 20/3 dB. The EMOEW has a small cross-section (0.42 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula> × 0.26 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula> ) and yields a cross-polarization discrimination of 27 dB at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$f_{0}$</tex-math></inline-formula> . The filtering antenna is fed by a propagating waveguide, making it suitable for high-power applications.