Shaoli Zuo

A New Compact Filter-Antenna for Modern Wireless Communication Systems

Design, fabrication, and measurement of a new compact filter-antenna for modern wireless communication systems are presented in this letter. Two microstrip square open-loop resonators, a coupled line, and a Γ-shaped antenna are used and integrated to be a filter-antenna. The Γ-shaped antenna is excited by a coupled line that is treated as the admittance inverter in filter design. The Γ-shaped antenna performs not only a radiator, but also the last resonator of the bandpass filter. Therefore, near-zero transition loss is achieved between the filter and the antenna. The design procedure follows the circuit approach-synthesis of bandpass filters. Measured results show that the filter-antenna achieves an impedance bandwidth of 16.3% (over 2.26-2.66 GHz) at a reflection coefficient |S11 | <; - 10 dB and has a gain of 2.41 dBi.

EIGENMODE DECOUPLING FOR MIMO LOOP-ANTENNA BASED ON 180 - COUPLER

A low-cost, high isolation, printed loop-antenna system for multiple-input multiple-output (MIMO) applications in the 2.4GHz WLAN band is presented. By feeding the orthogonal eigenmodes of the array, port decoupling (S21 < i20dB) with tightly coupled elements (only 0:07‚ separation) is obtained. The orthogonal eigenmodes are realized based on 180 - coupler. Then decoupled external ports of the feed network may be matched independently by using conventional matching circuits. With this low-cost and high isolation characteristic, it is very suitable for being embedded inside a wireless access point (AP).

Compact Open-Slot Antenna With Bandwidth Enhancement

A compact open-slot antenna for bandwidth enhancement is presented. Multiple resonances are generated by using an asymmetrical rectangular patch with the U-shaped open-slot structure. Two bevels are cut on the patch to improve the impedance matching. The proposed antenna provides a wide impedance bandwidth of 122% from 2.95 to 12.1 GHz with -10-dB return loss. It is shown that the impedance bandwidth can be enhanced from 28% to 122% by using different antenna types. Moreover, this slot antenna is with a small size of 24.5 × 24.5 × 1 mm3, while maintaining the ultrawideband (UWB) performance.

INVESTIGATIONS OF REDUCTION OF MUTUAL COUPLING BETWEEN TWO PLANAR MONOPOLES USING TWO λ/4 SLOTS

This article presents a simple structure for reducing mutual coupling between two diversity planar monopole antennas for WLAN 5.2/5.8GHz applications. The structure has two ‚=4 (‚- wavelength in the substrate) slots cut into the ground plane between the two monopoles. In 0.5‚o (‚o-wavelength in the air) of the antenna spacing, mutual coupling was i33:3, i21:1dB at 5.2, 5.8GHz, respectively. The lowest mutual coupling of i33:3dB was achieved at 5.2GHz, which are 20.8dB improvements over the reference.

A Y-Shaped Tri-Band Monopole Antenna with a Parasitic M-Strip for PCS and Wlan Applications

A Y-shaped tri-band monopole antenna is proposed in this paper. The antenna consists of a parasitic M-strip and an elliptical slot etched in the ground. With the helps of the parasitic M-strip and the slot, the Y-shaped monopole antenna can easily obtain tri-band characteristic. The proposed antenna has been constructed and tested. The simulated and measured results show that the proposed antenna has three good impedance bandwidths (VSWR < 2) of 220 MHz (about 26% centered at 1.85 GHz), 580 MHz (about 24% centered at 2.4 GHz) and 886 MHz (about 16% centered at 5.4 GHz), which make it easily cover the required bandwidths for PCS band (1850–1990 MHz), and WLAN band (2400–2480 MHz, 5150–5350 MHz, and 5725–5825 MHz) applications.

A SIMPLE FILTERING-ANTENNA WITH COMPACT SIZE FOR WLAN APPLICATION

This paper presents a simple microstrip flltering-antenna with compact size for WLAN application. The T-shape resonator through an inset coupling structure can be treated as the admittance inverter and the equivalent circuit of the flltering-antenna is exactly the same as the bandpass fllter prototype. With a little extra circuit area, the proposed flltering-antenna has almost twice wider bandwidth, good skirt selectivity and high suppression in the stopband compared to the conventional microstrip antenna.

Ultra-Wideband Cavity-Backed Bowtie Antenna for Pattern Improvement

The design and ultra-wideband performance of a cavity- backed bowtie antenna with the parasitic dipole and parasitic circular ring is presented. Besides the elliptical bowtie dipole and the taper feeding microstrip for obtaining ultra-wideband impedance characteristics, the parasitic dipole and parasitic circular ring to efiectively improve the radiation pattern can be used for obtaining the stable broadside unidirectional radiation patterns. An ultra-wideband impedance characteristic of about 118.2% for VSWR • 2 ranging from 2.75{10.7GHz is achieved. A unidirectional radiation pattern, a stable peak gain of around 7.4{10.8dBi and low cross polarization over the whole operating band are also produced. A prototype has been fabricated and tested, and the experimental results validate the design procedure.

Dual-Band CP Antenna With a Dual-Ring Cavity for Enhanced Beamwidth

A dual-band circularly polarized (CP) antenna with enhanced beamwidth is proposed in this letter. Stacked cone-patches including a small patch for upper band (1561 ± 2 MHz) and a large one for lower band (1268 ± 10 MHz) are used to achieve the dual-band operation behavior. To widen beamwidth for the two operation bands, a dual-ring cavity is employed for the proposed antenna. The dual-ring cavity is formed by a large ring and a small ring, which are used to improving the beam performance for lower and upper band, respectively. Over the dual-band of interests, the impedance bandwidth (VSWR ≤ 1.5) and the axial ratio below 3 dB are both satisfied. Wide 3 dB beamwidths of about 135 ° and 112 ° at center frequencies (1268, 1561 MHz) of the two bands are obtained, respectively. The high gains at the low elevation (θ = 80°), only about -0.03 dB and -0.57 dB at the two frequency points, are also achieved. With these good performances, the antenna is very suitable for navigation systems applications.

Printed 6-Element Dipole Array Antenna for Omnidirection Applied in WiMAX

Abstract-A collinear printed 6-element dipole array antenna for WiMAX application is presented. By employing loop-loaded structures, the better omnidirectional coverage is achieved. The array has shown a 7.2% bandwidth (VSWR≤1.5) of center frequency at about 3.5GHz for application in WiMAX. Its performance is relatively stable with 8dBi antenna gain and about ±0.5dBi of the un-roundness on horizontal plane. Design details of the proposed antenna and the results of both simulation and experiment are presented and discussed.

A Planar Meander Monopole Antenna for DVB-H/GSM/DCS Mobile Handsets

A novel planar meander monopole antenna can generate a wide operating band to cover the DVB-H band in the UHF frequency band (470–702 MHz) and mobile communication in the GSM850/900 (824–894 MHz/890–960 MHz) and DCS1800 (1720–1880 MHz) bands. By using the planar monopole type radiating element constructed with meander strips, the antenna provides a degree of miniaturization while retaining a wide impedance bandwidth. A prototype is constructed and tested, which shows that impedance bandwidths of 740 MHz (440–1180 MHz) and 220 MHz (1710–1930 MHz) within 3 : 1 VSWR are achieved. Moreover, it has good omni-directional radiation characteristics within its operation band with gain values larger than 2 dBi.