X-Band Dielectric Rod Antenna With Pre-Select Bandpass Filter

This paper presents a dielectric rod antenna integrated with a pre-select filter at X-band. The antenna and the pre-select filter are both 3D-printed in a single pass using ABS filament with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon = 2.6$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\tan (\delta)=0.0025$ </tex-math></inline-formula>. The pre-select filter section is designed based on variations in the waveguide’s cross-section, which is shielded by conductive paint, while the antenna section consists of a rectangular cross-section dielectric rod antenna. All sections of the pre-select frequency antenna are made to WR-90 standard waveguide dimensions, and prototypes of the antenna and pre-select frequency antenna have been built and measured. A passband bandwidth of 10% at a center frequency of 10.5 GHz for the pre-select frequency antenna is achieved, with the incorporated pre-select filter limiting the bandwidth of the X-band antenna, showing a considerable off-band rejection. The prototype shows a maximum peak realized gain of 13.1 dBi at 11 GHz, with a minimum side-lobe level of 12.29 dB.