Semiconductor-substrate integrated 3D-micromachined W-band helical antennas

• Published in: Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation pp. 1 - 2
• Main Authors: Somjit, N., Oberhammer, J.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.07.2012
• Subjects: Arrays; Gain; Helical antennas; Loaded antennas; Silicon; Substrates; System-on-a-chip
• ISBN: 1467304611; 9781467304610
• ISSN: 1522-3965; 1947-1491
• DOI: 10.1109/APS.2012.6349415

This paper investigates for the first time concepts of W-band dielectric-core helix antennas which are fabricated by three-dimensional micromachining into the volume of a semiconductor (high-resistivity silicon) wafer substrate. The maximum antenna gain is achieved by free-etching the antenna but loading the core of the helical antenna with a dielectric-rod tailor-made out of the substrate, and by properly modifying the geometry of the substrate-integrated ground plane. The simulation results show that an optimized antenna concept has a return loss S11 of -22.3 dB at the nominal frequency of 75 GHz, and a 3dB-bandwidth of 2.5 GHz. For the whole band from 69 to 84 GHz, the reflection coefficient is better than -10 dB. A maximum gain of 13.2 dB and a half-power beamwidth (HPBW) of smaller than 40° are obtained for a single antenna. The front-to-back (F/B) ratio is better than 23.5 dB with an axial ratio of 0.94. An eight-element helix line array is demonstrated and has a maximum gain of 22.3 dB with a HPBW of 7° in the y-z plane and an F/B ratio of 23.71 dB.