Low-Profile Dual-Band Filtering Antenna With a Shared SIW Cavity

An integrated low-profile dual-band filtering antenna is proposed in this letter. By reshaping a square substrate integrated waveguide (SIW) cavity, diagonal TE
₁₀₂
and TE
₂₀₁
modes could be excited at two different bands. Two pairs of quarter-wavelength patches serve as the radiators in conjunction with the reshaped SIW cavity. The coupling between the cavity and patches is realized by sparse vias. By this coupling method, the original dual-mode filtering response of SIW cavity could be well maintained. A novel folded structure was proposed to reduce the aperture size achieving unsplit radiation beams for both low and high bands. With this novel configuration, the antenna radiation and filtering performance are greatly improved. A prototype has been fabricated and measured. Measured results agree well with the simulation, demonstrating good performance in terms of dual-band filtering, out-of-band rejection, radiation efficiency, and gain at two bands.