Kung Bo Ng

60 GHz Plated Through Hole Printed Magneto-Electric Dipole Antenna

A wideband unidirectional antenna, which is composed of a planar electric dipole and a magnetic dipole formed by a vertically-oriented shorted patch antenna, is presented for millimeter wave applications. The antenna is realized by a plated through hole printed technique with the use of a microwave substrate and is excited by a T-shaped coupled strip feed. An impedance bandwidth of 33% (S11 ≤-15 dB) from 50 to 70 GHz is achieved. Stable radiation patterns with low cross polarizations and a stable antenna gain of ~7.5 dBi are achieved across the entire operating bandwidth. This single antenna element yields advantages of wideband, good directional radiation pattern and low fabrication cost.

Small Circularly Polarized U-Slot Wideband Patch Antenna

A single-feed circularly polarized (CP) patch antenna at L-band is designed and built using the recently developed U-slot loaded patch technique. With the presence of the U-slot, the antenna fabricated on a high-dielectric-constant (ε_r = 10.02) substrate achieves a reasonable axial-ratio bandwidth. At the operating frequency of 1.575 GHz, the size of the patch is 0.13λ_o × 0.13λ_o, while the ground size is 0.315λ_o × 0.315λ_o and the thickness of the substrate is 0.05λ_o. The measured gain is 4.5 dBi, and axial-ratio bandwidth is 3.2%.

Virtually Shorted Patch Antenna for Circular Polarization

This letter presents a new circularly polarized patch antenna with loaded shorting elements to achieve symmetric broadside radiation and size reduction. The loaded elements are parasitic to the driven patch, but are shorted to the ground plane. Conventionally, shorting pins or walls are a common technique for reducing the size of the antenna. However, deterioration in broadside radiation with high cross-polar level occurs. The proposed shorting elements provide a solution for size reduction of the radiating patch while maintaining good broadside radiation pattern. Since the radiating patch is effectively shorted to the ground at the operating frequency, it is designated as a virtually shorted patch antenna (VSPA).

Controlling Dispersion Characteristics of Terahertz Metasurface

Terahertz (THz) metasurfaces have been explored recently due to their properties such as low material loss and ease of fabrication compared to three-dimensional (3D) metamaterials. Although the dispersion properties of the reflection/transmission-type THz metasurface were observed in some published literature, the method to control them at will has been scarcely reported to the best of our knowledge. In this context, flexible dispersion control of the THz metasurface will lead to great opportunities toward unprecedented THz devices. As an example, a THz metasurface with controllable dispersion characteristics has been successfully demonstrated in this article, and the incident waves at different frequencies from a source in front of the metasurface can be projected into different desired anomalous angular positions. Furthermore, this work provides a potential approach to other kinds of novel THz devices that need controllable metasurface dispersion properties.

Millimeter-Wave Low Temperature Co-Fired Ceramic Leaky-Wave Antenna and Array Based on the Substrate Integrated Image Guide Technology

A substrate integrated image guide (SIIG) transmission line is realized based on the low temperature co-fired ceramic (LTCC) technology. Compared with other existed SIIGs, this configuration not only offers simplicity in designing procedures, but also provides better fabrication reliability. Due to its extremely low loss, this type of SIIG can be applied in millimeter-wave high-efficiency antenna designs. A V-band periodic leaky-wave antenna fed by a coplanar-waveguide (CPW) and a W-band single-port periodic leaky-wave antenna fed by a substrate integrated waveguide (SIW) are developed in this paper. Then, eight W-band antennas are grouped as an array, which is fed by a WR-10 waveguide through an SIW divider. Experimental results validate our analysis and design.

Bandwidth Enhancement of Planar Slot Antenna Using Complementary Source Technique for Millimeter-Wave Applications

Traditional coplanar waveguide (CPW)-fed planar slot antennas are inherently narrow in bandwidth. Widening open-ends of the slot and adding parasitic elements are popular techniques for bandwidth enhancement. An alternative approach is to apply complementary sources. In this paper, a new stacked structure of complementary antenna is proposed which utilizes a traditional CPW-fed slot antenna to act as a magnetic source and a parasitic dipole located across the slot to act as an electric source. This antenna array, fabricated on generic microwave substrate with simple plated-through-hole, printed-circuit technology, the measured impedance bandwidth can cover from 55 to 67 GHz for VSWR ≤ 3.0. It achieves a maximum measured gain of 12.2 dBi at 65 GHz and above 10.0 dBi in the passband from 56 to 67 GHz for 60-GHz application.

Millimeter-Wave Cavity-Backed Patch-Slot Dipole for Circularly Polarized Radiation

A novel millimeter-wave antenna for circularly polarized (CP) radiation is presented. The proposed antenna is composed of a patch dipole and a slot dipole, and it is realized by a plated through hole printed technique on a microwave substrate. Simulations show that the antenna can present a bandwidth from 55.8 to 65.3 GHz for a reflection coefficient (S11) ≤ -10 dB as well as for an axial ratio (AR) ≤ 3dB, and the 9.6 dBi average gain is achieved. This design yields good directional radiation patterns and low fabrication cost. Studies on several critical parameters are performed for practical designs.

Waveguide Fed Broadband Millimeter Wave Short Backfire Antenna

A broadband millimeter-wave short backfire antenna (SBA), excited by a bowtie dipole and fed by an E-band rectangular waveguide, is presented in this paper. Its subreflector is replaced by two simple strips printed on the opposite sides of the same supporting substrate of the bowtie exciter for ease and accuracy of fabrication. For reference of practical designs, detailed parametric studies are performed in this paper. Measurements and simulations show that the proposed antenna can feature an improved operating bandwidth and broadside gain compared to the previously reported conventional SBAs. The measured impedance bandwidth for SWR

Low-cost discrete dielectric terahertz lens antenna using 3D printing

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Wideband shorted higher-order mode millimeter-wave patch antenna

2 is 57%, from 55.7 to 100 GHz, in which the measured broadside gain is from 13.8 to 18.5 dBi with the peak gain at 85 GHz. Finally, high illumination efficiency of the bowtie exciter is highlighted by comparisons with a straight dipole excited SBA.