Ramadan A. Alhalabi

High-Gain Yagi-Uda Antennas for Millimeter-Wave Switched-Beam Systems

A high-efficiency microstrip-fed Yagi-Uda antenna has been developed for millimeter-wave applications. The antenna is built on both sides of a Teflon substrate (epsivr = 2.2) which results in an integrated balun for the feed dipole. A 7-element design results in a measured gain of 9-11 dB at 22-26 GHz with a cross-polarization level of < - 16 dB. The antenna is matched to 50 Omega (microstrip feed). A mutual coupling of < - 20 dB is measured between two Yagi-Uda antennas with a center-to center spacing of 8.75 mm (0.7 lambda0 at 24 GHz), and a two-element array results in a measured gain of 11.5-13 dB at 22-25 GHz. The planar Yagi-Uda antenna results in high radiation efficiency ( > 90 % ) and is suitable for mm-wave radars and high data-rate communication systems.

Millimeter-Wave Wafer-Scale Silicon BiCMOS Power Amplifiers Using Free-Space Power Combining

This paper presents the first millimeter-wave wafer-scale power-amplifier array implemented in a 0.13-μ m BiCMOS technology. The power combining is done in the free-space using high efficiency on-chip antennas. A 3 × 3 power-amplifier array is demonstrated with an equivalent isotropic radiated power of 33-35 dBm at 90-98 GHz. This results in a total on-chip power of 21-23 dBm and a total radiated power of 17.5-19.5 dBm. The measured patterns of the array show single-mode operation and ~100% free-space power-combining efficiency with a 3-dB beamwidth of 28° and a directivity of 15.5 dB (gain of 12 dB). The total power-combining efficiency including the antenna losses is 45±10%. The application areas are in millimeter-wave transmitters and wafer-scale phased arrays.

High-Efficiency Angled-Dipole Antennas for Millimeter-Wave Phased Array Applications

A high-efficiency microstrip-fed endfire angled-dipole antenna has been developed for millimeter-wave phased array applications. The antenna is built on both sides of a Teflon substrate (epsivr = 2.2) and this 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 lambda0 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 (including mismatch loss). 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 degrees. The application areas are in automotive radars and high data-rate communication systems.

Self-Shielded High-Efficiency Yagi-Uda Antennas for 60 GHz Communications

A high-efficiency self-shielded microstrip-fed Yagi-Uda antenna has been developed for 60 GHz communications. The antenna is built on a Teflon substrate (εr = 2.2) with a thickness of 10 mils (0.254 mm). A 7-element design results in a measured S11 of <; -10 dB at 56.0 - 66.4 GHz with a gain >; 9.5 dBi 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 from 2 mm to 11 mm, and the Yagi-Uda antenna results in a gain >; 12 dBi 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.

A 3 G-Bit/s W-band SiGe ASK receiver with a high-efficiency on-chip electromagnetically-coupled antenna

A novel high-efficiency on-chip W-Band microstrip antenna is designed in a commercial SiGe process (IBM 8HP). The antenna has a measured gain of 2–4 dB and an efficiency of 50–57% at 92–98 GHz. An ASK receiver including a W-Band SPDT, LNA, and power detector is integrated with the antenna and is used to demonstrate a low-power 94 GHz 3-Gb/s on-chip wireless data link.

Differentially-Fed Millimeter-Wave Yagi-Uda Antennas With Folded Dipole Feed

Differentially-driven Yagi-Uda antennas have been developed for millimeter-wave applications. The antennas are built on both sides of a Teflon substrate (¿r = 2.2). A key design aspect is the use of a folded dipole feed which increases the input impedance from 18 ¿ (standard dipole case) to 150 ¿ and is compatible with coplanar strip lines. A 7-element design results in a gain of 8-10 dB at 22-26 GHz and a cross-polarization level of < -22 dB. The differentially-fed Yagi-Uda antenna with folded dipole results in high radiation efficiency ( > 90% at 22-26 GHz) and is suitable for mm-wave point-to-point links communication systems.

Design of high-efficiency millimeter-wave microstrip antennas for silicon RFIC applications

This paper presents the design information for a W-band high-efficiency, electromagnetically-coupled on-chip silicon microstrip antenna. 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 a measured S11 bandwidth of 91.5–98.5 GHz, a measured gain of 0.7–3.9 dB and a radiation efficiency of 48 +/−8% at 91–100 GHz. The design is scalable to N×M elements and to wafer-scale arrays. The application areas are in wafer-scale phased arrays, on-chip low-power sensors, communication systems, and mm-wave collision avoidance radars. To our knowledge, this is the highest gain and efficiency silicon on-chip antenna at mm-wave frequencies.

Wafer-scale W-band power amplifiers using on-chip antennas

This paper presents, for the first time, a W-band SiGe power amplifier designed and fabricated together with a high-efficiency on-chip microstrip antenna. The antenna/amplifier results in an effective radiated power (ERP=PtGt) ≫ 10 dBm from 88 to 98 GHz, with a peak of 14.6 dBm at 92 GHz. The chip consumes 120 mA from a 1.7 V supply. The antenna/amplifier approach can be extended to a large number of elements (8×8) and allows for efficient wafer-scale power combining and phased-array scanning.

High-gain quasi-shielded tapered-slot antennas for 50–65 GHz switched-beam systems

A tapered-slot antenna (TSA) with microstrip-to-slotline transition is demonstrated for millimeter-wave wireless communications. Two antennas with different aperture widths and lengths are fabricated on a Teflon substrate (εr = 2.2, t = 10 mils), and result in a measured S11 &#60; −8 dB with a gain of 11 dB and 7 dB at 55–63 GHz for an aperture of 3.5 mm and 1 mm, respectively. To validate its performance inside portable mm-wave systems, two metal shielding planes are placed above and below the antennas. The results show that the TSAs maintain good impedance matching and gain with a metal plane height of 1–3 mm, depending on the aperture. A four-element TSA array is also demonstrated for switched-beam systems.

High-efficiency 60 GHz dipole-box antennas

In this paper, a 60 GHz dipole antenna with excellent performance such as wideband impedance matching, medium gain and high efficiency (> 90%) is designed and tested. Also, the antenna is then placed inside a metal box and tested. The dipole-box antenna not only maintains good impedance matching but also demonstrates a gain of 10–11 dB and narrower H-plane radiation patterns than the standard dipole antenna. The dipolebox antenna is ideal for placement inside a laptop or a portable 60 GHz communications device since it is shielded from the environment and is not affected by nearby metals.