K.L. Lau

A wide-band monopolar wire-patch antenna for indoor base station applications

This paper presents the design and testing of a wide-band monopolar wire-patch antenna. The proposed antenna consists of a circular patch that is shorted to the ground plane by four copper wires and is fed by an L-probe at its center. For the patch height and patch radius of 0.092 and 0.179 free space wavelengths at 0.893 GHz, this antenna possesses a 14-dB return loss bandwidth of 27.1%, which is 9 times wider than that of similar type of antenna reported in the literature. Also, it has an average gain of 2.6 dBi and monopole-like radiation patterns over this bandwidth. As this antenna has wide impedance bandwidth and relatively small size, it is very suitable for the indoor mobile communication systems.

Design of a circularly-polarized vertical patch antenna

A circularly-polarized vertical patch antenna is proposed and investigated. The design is achieved by simply adding two small stubs to the vertical patch. The antenna maintains the advantages of the original linearly polarized vertical patch antenna, such as simple structure, small size and wide bandwidth. It exhibits a gain of 8 dBi over a 3 dB axial ratio bandwidth of 4%.

A Wideband Dual-Polarized L-Probe Stacked Patch Antenna Array

A 2 times 1 dual-polarized L-probe stacked patch antenna array is presented. It has employed a novel technique to achieve high isolation between the two input ports. The proposed antenna has a 14-dB return loss bandwidth of 19.8%, which is ranged from 0.808 to 0.986 GHz, for both ports. Also, it has an input port isolation of more than 30 dB and an average gain of 10.5 dBi over this bandwidth. Moreover, its radiation patterns in the two principal planes have cross-polarization level of less than -15 dB within the 3-dB beamwidths across the passband. Due to these features, this antenna array is highly suitable for the outdoor base station that is required to cover the operating bandwidths of both CDMA800 and GSM900 mobile communication systems.

A wide-band dual-polarization patch antenna with directional coupler

A broad-band dual-polarization patch antenna fed by L-shaped probes at the patch corners is presented. A coupled line directional coupler mounted at the back of the ground plane is used to enhance the isolation between the L-probes to a large extent. Through using the coupler to feed the L-probes, the isolation between the input ports is 34 dB over the GSM900 operating bandwidth, which has enhanced by 14 dB. By using two plastic spacers of 0.1/spl lambda//sub o/ in height to support the patch in the air, an impedance bandwidth of 18% (for S/sub 11//spl les/-14 dB), and an average gain of 7 dBi can be obtained for both ports. The far field patterns are stable across the passband. This antenna can potentially be used as a GSM900 base station antenna.

A full-wavelength circularly polarized slot antenna

A new single-feed technique for high gain operation of the circularly polarized cross-slot antenna backed by a ground reflector is presented. The antenna, which has a size of one wavelength, exhibits a gain of 11 dBi over a 3 dB axial ratio bandwidth of 5%. Simulations are performed using an EM simulator IE3D and agree well with experimental results.

Wideband Folded Feed L-Slot Folded Patch Antenna

A newly developed patch antenna, designated as the folded feed L-slot folded patch antenna, is presented in this letter. It consists of an L-slot folded patch that is shorted to the ground plane by a metallic wall and is fed by a folded structure. The patch has profile of 0.24lambda and length of 0.4lambda, where lambda is the free-space wavelength at the center frequency of its operating bandwidth. This antenna has impedance bandwidth of 133.3% (0.72 to 3.60 GHz) for SWR les 2, which is the largest value that can be achieved by a shorted wall patch antenna in the literature. As the proposed antenna can achieve such wide impedance bandwidth, it is very suitable for the multiband wireless communication systems nowadays.

A Vertical Patch Antenna for Dual-Band Operation

A new dual-band vertical patch antenna for broadside radiation is described. The antenna is fed by a proximity-coupled probe, which maintains the advantages of the original single-band vertical patch antenna, such as small size, wide bandwidth and simple structure. The achieved bandwidths are 7% and 26%, respectively, at the lower and upper frequency bands.

A novel wideband circularly polarized patch antenna based on L-probe and slot-coupling techniques

The design and measurements of a wideband patch antenna with circular polarization are presented. For the proposed antenna, an L-probe and a coupling aperture are utilized to feed the patch orthogonally. The distance between the patch and the ground plane is 0.1 free space wavelength at 18 GHz. The patch is supported by plastic posts in the air. A Wilkinson power combiner is connected to the feeds to generate circular polarization. The antenna possesses a 14 dB return loss bandwidth of 35% (from 1.49-2.12 GHz), and it has a 3 dB axial ratio bandwidth of 20.4% (from 1.67-2.05 GHz) The 3 dB axial ratio beamwidth and the bore sight axial ratio are 840 and 1.94 dB at 1.8 GHz, respectively.

Dual linear polarization patch antenna array with high isolation

This paper describes the design and experimental results of a wideband dual linear polarization patch antenna array for PCS base stations. This antenna is designed to operate from 1.71 to 1.88 GHz, centered at 1.8 GHz. It is built as two sets of 2/spl times/1 antenna arrays working with linear polarization that is perpendicular to each other. The impedance bandwidth (return loss better than -14 dB and -10 dB) of this antenna array is 20% and 26% respectively. The isolation between the +45/spl deg/ and -45/spl deg/ ports of the array is 50 dB at the center frequency and better than 34 dB over the operating range. The diversity gain is about 10.5 dB at the center frequency.

A wideband C-shaped vertical patch antenna

A wideband vertical patch antenna (VPA) is depicted, which is devised from a single circular vertical patch. Without increasing the projection area, a C-shaped proximity-coupled fed VPA with 40% bandwidth and over 6 dBi gain across entire frequency band is designed and tested. Stable and broadside patterns are maintained across the matching band.