Skip to main content
eScholarship
Open Access Publications from the University of California

UC San Diego

UC San Diego Electronic Theses and Dissertations bannerUC San Diego

High efficiency planar and RFIC-based antennas for millimeter-wave communication systems

  • Author(s): Alhalabi, Ramadan A.;
  • et al.
Abstract

The dissertation presents the design and measurements of several planar and RFIC-based high efficiency antennas for mm-wave applications. The high-efficiency microstrip-fed endfire angled-dipole antenna is designed mainly for phased-array applications. It is built on both sides of a Teflon substrate ([epsilon]r = 2.2) and allows a wideband feed from the single-ended microstrip line to the differential dipole. The design results in wide radiation patterns for scanning purposes with a gain of around 2.5 dB at 20 - 26 GHz and a cross-polarization level of < -15 dB at 24 GHz. A mutual coupling of < -23 dB is measured between adjacent elements with 6.8 mm center-to center spacing (0.50 - 0.54[lambda]0 at 22 - 24 GHz). A variant of the angled-dipole antenna with a magnetic ground plane edge was also developed, and shows a measured gain of > 6 dB at 23.2 - 24.6 GHz and very low mutual coupling between elements (< -23 dB for a 6.8 mm spacing). Both antennas result in a radiation efficiency of > 93% when referenced to the microstrip line feed. The usefulness of these antennas as phased-array radiators is demonstrated by several eight-element linear arrays at 22 - 24 GHz with scan angle up to 50°. High-efficiency microstrip-fed and CPS-fed Yagi-Uda antennas have also been developed for point-to-point millimeter-wave communication systems. The antennas are built on Teflon substrates ([epsilon]r< = 2.2) ; and utilize 5 directors to result in a gain of 8 - 12 dB at 24 GHz and 60 GHz. A mutual coupling of < -20 dB is measured between two microstrip-fed Yagi-Uda antennas with a center-to center spacing of 8.75 mm (0.7[lambda]0 at 24 GHz), and a two-element array results in a measured gain of 11.5-13.0 dB at 22-25 GHz. The planar Yagi-Uda antennas result in high radiation efficiency (> 90%) and is suitable for short-range mm-wave radars and high data- rate communication systems. A differential version was also developed using a folded dipole feed and is compatible with fully-differential RFICs. Self-shielded microstrip-fed Yagi-Uda antenna has also been developed for 60 GHz communications. The antennas are built on a Teflon substrates ([epsilon]r = 2.2) with a thickness of 10 mils (0.254 mm). A 7-element design results in a gain > 9.5 dB at 58 - 63 GHz. The antenna shows excellent performance in free space and in the presence of metal- planes used for shielding purposes. A parametric study is done with metal plane heights (h) from 2 mm to 11 mm, and the Yagi-Uda antenna results in a gain > 12 dB at 58 - 63 GHz for h = 5 - 8 mm. A 60 GHz four-element switched-beam Yagi-Uda array is also presented with top and bottom shielding planes, and allows for 180° angular coverage with < 3 dB amplitude variations. This antenna is ideal for inclusion in complex platforms, such as laptops, for point-to-point communication systems, either as a single element or a switched-beam system. MM-wave planar monopole antennas have been also demonstrated. A triangular and a straight monopole antennas result in a measured S₁₁ < -10 dB at 20.7 - 37.9 GHz and 18 - 42 GHz respectively. Both antennas are suitable for ultra-wideband applications. These antennas show omni-directional patterns over almost the whole bandwidth but with high cross-polarization levels ( ̃equal to the co-polarization level). An alternate monopole design with a localized folded current choke was developed and results in lower cross-polarization levels ( -6 dB), but with S₁₁ < -10 dB at 23.1 - 26.7 GHz. A variant of this design with a magnetic ground plane results in substantial reduction in the cross-polarization level (-13 dB) but with a bandwidth of only 1 GHz (S₁₁ < - 10 dB at 23.5 - 24.8 GHz). The measured gain of the antennas are in the range of -4.0 dB to + 2.9 dB, depending on the design, and with high radiation efficiency (> 90%). Finally, a W-band high-efficiency, electromagnetically-coupled on-chip silicon microstrip antenna has been demonstrated. The antenna is composed of a quartz substrate placed on top of a commercial low- resistivity SiGe BiCMOS silicon chip. Design criteria for the microstrip antenna taking into account the dielectric and metal-density rules for the different layers of the BiCMOS silicon chip are presented. The antenna results in Sv(1)v(1) < -10 dB at 91.7 - 98.5 GHz, a gain of 0.7 - 3.9 dB and a radiation efficiency of 44 +/- 13% at 91 - 100 GHz. The design is scalable to NxM elements and to wafer-scale arrays. To our knowledge, this is the first high- efficiency Silicon wafer-scale antenna to date

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View