Design of an Amplitude-Tapered Corporate-Feed Slot Array Antenna with Reduced Side-Lobe Level for Silicon Micromachining

Abstract

This work proposes a novel unbalanced corporatefeed network antenna design with amplitude tapering of the radiated power to get a reduced sidelobe level. The phase imbalance of the asymmetric power dividers is compensated by integrated delay lines which maintain the aperture efficiency. The 10 dB beamwidth is reduced by 8.5% in E-plane and 10.2% in H-plane after the phase compensation. A 𝟏𝟔 × 𝟏𝟔 and a 𝟑𝟐 × 𝟑𝟐 array antenna have been designed for 230-290 GHz, i.e., a 23% fractional bandwidth. The 𝟏𝟔 × 𝟏𝟔 and 𝟑𝟐 × 𝟑𝟐 antenna's realized gain is between 29.4-32.1 dBi and 34.6-37.6 dBi, with sidelobe levels better than 21.2 dB and 20.5 dB, respectively. The design is optimized for being implemented by silicon micromachining. To the best of the author's knowledge, this is the first amplitude tapered corporate feed slot array antenna with delay lines for phase compensation that has been proposed in this frequency range with this wide operational bandwidth.

Silicon-Micromachined Subterahertz Frequency Beam-Steered Dual-Port Array Antenna

“…2c, the first two dividing steps utilize Tjunction power dividers with inductive posts [35], [36], and the third dividing step uses Y-junction power dividers [37]. In addition, the phase imbalance imposed by the unequal dividing ratios of the unbalanced power dividers is minimized by integrated delay sections in every individual branch [22]. The normalized amplitude distribution and the normalized residual phase error of each branch at 243 GHz are shown in Fig.…”

“…Substrate loss plays an essential role in the efficiency of sub-THz antennas, so substrate-based arrays suffer from more loss and lower total efficiency compared to hollow waveguide arrays. As a result, utilizing silicon micromachining to implement planar antenna arrays based on hollow waveguides is preferred for systems operating in the sub-THz frequency range, especially above 200 GHz, due to their unique features, including low loss, high gain, high integrability, and high compatibility with SLL reduction techniques [22].…”