Le Kang

DUAL-WIDEBAND SYMMETRICAL G-SHAPED SLOTTED MONOPOLE ANTENNA FOR WLAN/WIMAX APPLICATIONS

A novel dual-wideband printed monopole antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed antenna consists of a T-shaped monopole on top and dual combined G-shaped slots etched symmetrically on the ground plane to achieve a dual-wideband performance. Prototype of the proposed antenna has been constructed and tested. The measured 10dB bandwidths for return loss are 1.76GHz from 2.13 to 3.89GHz and 0.92GHz from 5.03 to 5.95GHz, covering all the 2.4/5.2/5.8GHz WLAN and 2.5/3.5/5.5GHz WiMAX bands. And this antenna also has omni-directional patterns over the lower operating range.

A NOVEL RECTANGULAR SLOT ANTENNA WITH EMBEDDED SELF-SIMILAR T-SHAPED STRIPS FOR WLAN APPLICATIONS

A novel rectangular slot antenna with embedded self- similar strips is proposed for wireless local area network (WLAN) applications. The proposed antenna comprises a T-shaped monopole and inverted self-similar strips embedded in the rectangular slot etched on the ground plane. The measured results of the fabricated antenna show that the impedance bandwidths (VSWR < 2) are 180MHz from 2.36 to 2.54GHz and 920MHz from 5.05 to 5.97GHz, which cover all the 2.4/5.2/5.8GHz WLAN operating bands. And the radiation patterns are almost omni-directional in the azimuthal plane within the lower operating bands.

A Novel Tri-Band Printed Monopole Antenna with an Etched ∩-Shaped Slot and a Parasitic Ring Resonator for WLAN and WiMAX Applications

A novel tri-band printed monopole antenna with an etched \-shaped slot and a parasitic ring resonator is proposed for satisfying wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications simultaneously. The proposed antenna comprises a rectangular radiation patch with an arc- shaped edge and an embedded \-shaped slot on the top and a parasitic ring resonator on the opposite side. The measured results show that the impedance bandwidths of the proposed antenna, deflned by voltage standing wave ratio (VSWR) • 1:5, are 350MHz (2370{2720MHz), 680MHz (3390{4070MHz) and 1080MHz (4920{6000MHz), which cover the required bandwidths for both WLAN (2400{2480MHz, 5150{5350MHz, 5725{5825MHz) and WiMAX (2500{2690MHz, 3400{3690MHz, 5250{5850MHz) applications. Furthermore, good monopole-like radiation characteristics with moderate peak gains are obtained over the operating bands.

A NOVEL SELF-SIMILAR ANTENNA FOR UWB APPLICATIONS WITH BAND-NOTCHED CHARACTERISTICS

A novel self-similar antenna for band-notched ultra- wideband (UWB) applications is proposed. The UWB performance is obtained by introducing a quasi-trapezoidal radiating patch and a self-similar ground plane. By etching two similar slots on the radiating patch, band-notched characteristic can be obtained. The measured results show that the antenna covers the band of UWB from 2.6 to 12.8GHz excluding the rejected bands from 3.3 to 3.6GHz and from 4.8 to 6.0GHz. In addition, the antenna exhibits nearly omni-directional radiation patterns and stable gains over the operating bands.

Planar Dual-Band Power Divider with Short-Circuited Stub

A novel planar dual-band microstrip power divider is proposed in this paper. The circuit is composed of two sections of transmission line, short-circuited stub line and planar resistor, which can provide high isolation and good amplitude balance simultaneously at two frequencies. The closed-form equations are derived, and the design procedures of dual-band power divider are given. To certify the validity, a proposed power divider was fabricated and measured at 950 MHz and 2200 MHz which might be applied to GSM and CDMA systems. Both theoretical and simulated results are given, which are in good agreement with the measured results.

Novel smiling face-shaped antenna for dual band-notched ultra-wideband applications

This article presents the design of a novel ultra-wideband microstrip fed planar monopole antenna with dual band-notched characteristics. The shape of the antenna is a smiling face with double braids; its lovely and simple design has advantage to beatify the product By etching a mouth-shaped slot in the radiating patch and adding a double braids-shaped strip on the top, the dual notched bands for WiMAX and WLAN applications can be obtained, respectively. The eyes-shaped slots are just designed for beatification without affecting the characteristic of radiation. The simulated and measured results show that the center frequencies of the notched bands are greatly affected by the flare angle of the double braids-shaped strip and the mouth-shaped slot The fabricated antenna shows the broadband impedance-matching, stable gain, and near omnidirectional radiation pattern.

Design of Tri-Band Quasi-Self-Complementary Antenna for WLAN and WiMAX Applications

In this article, a novel printed quasi-self-complementary antenna with tri-band characteristic is presented for WLAN and WiMAX applications. A triangular quasi-self-complementary structure, which consists of a radiating patch and its counterpart slot on the ground, is employed to produce two operating bands centered at about 2.5 and 5.2 GHz. Then, by introducing a rectangular slit cut from the patch and its complementary mirror image strip inserted into the slot, an additional resonance at 3.5 GHz is excited and tri-band operation can be realized. A prototype of the proposed antenna has been successfully fabricated and measured. Both the simulated and measured results are obtained to demonstrate the promising performance required for practical applications. Based on the results, it is shown that 10-dB impedance bandwidths of the proposed antenna are 510 MHz (2.25-2.76 GHz), 330 MHz (3.38-3.71 GHz), and 770 MHz (5.1-5.87 GHz), respectively. Also, nearly omnidirectional radiation patterns and acceptable antenna gains can be achieved over the three operating bands.

A Broadband Circularly Polarized Antenna Based on Cross-Dipoles

In this paper, based on cross-dipoles, a right-handed circularly polarized (RHCP) antenna with both broad impedance and axial-ratio (AR) bandwidth is proposed. Moreover, metal vias and branches are loaded to the cross-dipoles aiming to decrease the size of the antenna. The measured results show that a broadband impedance matching bandwidth ranging from 1.83 to 3.42 GHz for S11 less than �10 dB is obtained. Meanwhile, the 3-dB axial-ratio bandwidth is more than 29.0%, and the peak gain of the antenna is about 7.3 dBi with small variation at 2.5 GHz. A prototype is fabricated and measured for validating the design. The good agreements between the simulated and measured results show that the proposed antenna maybe a good candidate in circularly polarized (CP) antenna family.