Slots or defects integrated on the ground plane of microwave planar circuits are referred to as Defected Ground Structure. DGS is adopted as an emerging technique for improving the various parameters of microwave circuits, that is, narrow bandwidth, cross-polarization, low gain, and so forth. This paper presents an introduction and evolution of DGS and how DGS is different from former technologies: PBG and EBG. A basic concept behind the DGS technology and several theoretical techniques for analysing the Defected Ground Structure are discussed. Several applications of DGS in the field of filters, planar waveguides, amplifiers, and antennas are presented.

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Defected Ground Structure: Fundamentals, Analysis, and Applications in Modern Wireless Trends

A compact triple-band microstrip slot antenna applied to WLAN/WiMAX applications is proposed in this letter. This antenna has a simpler structure than other antennas designed for realizing triple-band characteristics. It is just composed of a microstrip feed line, a substrate, and a ground plane on which some simple slots are etched. Then, to prove the validation of the design, a prototype is fabricated and measured. The experimental data show that the antenna can provide three impedance bandwidths of 600 MHz centered at 2.7 GHz, 430 MHz centered at 3.5 GHz, and 1300 MHz centered at 5.6 GHz.

A Compact Microstrip Slot Triple-Band Antenna for WLAN/WiMAX Applications

A novel triband square-slot antenna with symmetrical L-strips is presented for WLAN and WiMAX applications. The proposed antenna is composed of a square slot, a pair of L-strips, and a monopole radiator. By employing these structures, the antenna can yield three different resonances to cover the desired bands while maintaining small size and simple structure. Based on this concept, a prototype of a triband antenna is designed, fabricated, and tested. The experimental results show the antenna has the impedance bandwidths of 480 MHz (2.34-2.82 GHz), 900 MHz (3.16-4.06 GHz), and 680 MHz (4.69-5.37 GHz), which can cover both WLAN in the 2.4/5.2-GHz bands and WiMAX in the 2.5/3.5-GHz bands.

Compact Triband Square-Slot Antenna With Symmetrical L-Strips for WLAN/WiMAX Applications

This paper presents a compact dual-band slot antenna for 2.4/5 GHz WLAN applications. The radiating elements of the proposed antenna are composed of a square ring slot and a circular ring slot, operating at 2.4 GHz and 5 GHz bands respectively. The antenna size is very compact (40 mm × 40 mm × 1 mm), and can be integrated easily with other RF front-end circuits. It is demonstrated that the proposed antenna can completely cover the required bandwidths of IEEE 802.11b/g (2.4–2.485 GHz) and IEEE 802.11a (5.15–5.825 GHz) with satisfactory radiation characteristics. Good agreement is achieved between the simulated and measured results.

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Compact Dual-Band Slot Antenna for 2.4/5ghz WLAN Applications

There are two novel printed inverted-F antenna (PIFA) related dual-band antennas for 2.45 and 5.25 GHz wireless local area network (WLAN) applications introduced in this paper. One is designed by spiraling the tail of the PIFA and the other is by modifying the feed structure of the PIFA into a coupling configuration. An equivalent transmission line model is proposed to explain the dual-band operation of the spiraling PIFA. The measurement results show that the former antenna has a 10 dB return loss with bandwidth 140 MHz in the 2.45 GHz frequency band and bandwidth 756 MHz at 5.25 GHz, whereas the latter one has the bandwidth 240 MHz at 2.45 GHz and bandwidth 672 MHz at 5.25 GHz. In addition, omnidirectional radiation patterns are achieved at those operating frequency bands with average antenna gains near 0 dBi. The proposed antenna possesses the properties of good performance, compact size (about 50% of a typical PIFA), low profile, and low cost; hence, it is suitable for practical applications in a combo WLAN system

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Two PIFA-Related Miniaturized Dual-Band Antennas

A novel dual broadband rectangular slot antenna for 2.4 and 5 GHz wireless local area network (WLAN) is proposed. With the use of a U-shaped strip inset at the centre of the rectangular slot antenna, the obtained impedance bandwidths for two operating bands can reach about 10.6% for the 2.4 GHz band and 33.8% for the 5 GHz band, which cover the required bandwidths of IEEE 802.11b/g (2.4-2.484 GHz) and IEEE 802.11a (5.150-5.950 GHz). Details of the antenna design and experimental results are presented and discussed.

Dual broadband design of rectangular slot antenna for 2.4 and 5 GHz wireless communication

A novel compact dual-band equilateral-triangular slot antenna (ETSA) for 2.4/5-GHz wireless local area networks (WLANs) is presented. A pair of F-shaped strips are centrally inset at the side edge of the ETSA to extend the surface-current path of dual operating bands in order to lower both operating frequencies simultaneously. And, the obtained impedance bandwidths cover the required bandwidths of IEEE 802.11b/g (2400–2484 MHz) and IEEE 802.11a (5150–5950 MHz). The measured antenna radiation patterns are approximately bidirectional at the two resonant frequencies. Peak antenna gains for the operating frequencies across dual WLAN bands are measured to be, respectively, 2.8 and 5 dBi with gain variations within 1.0 dBi. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 81–84, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20730

2.4/5-GHz dual-band triangular slot antenna with compact operation

A novel design of rectangular slot-antenna with dual-broadband operation for 2.4/5-GHz wireless local area networks (WLANs) is proposed. With the use of two rectangular strips inset along the center line of the rectangular-slot antenna, a new resonant mode close to the second operating mode of the regular rectangular slot antenna is excited to enhance the operating bandwidth of the higher band. And, the obtained impedance bandwidths for two operating bands can reach about 11% for the 2.4-GHz band and 24.8% for the 5-GHz band and cover the required bandwidths of IEEE 802.11b/g (2.4–2.484 GHz) and IEEE 802.11a (5.150–5.950 GHz). Details of the antenna design and the experimental results are presented and discussed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 197–201, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20944

Novel dual-broadband rectangular-slot antenna for 2.4/5-GHz wireless communication

A novel dual-broadband T-shaped monopole antenna with dual shorted L-shaped strip-sleeves for 2.4/5.8-GHz wireless local area networks (WLANs) is proposed. Dual L-shaped strip-sleeves to be shorted with the ground plane are introduced in order to excite the upper resonant mode for operation at the 5.8-GHz band. The obtained impedance bandwidths reach about 35% for the 2.4-GHz band and 10.0% for the 5.8-GHz band, which meets the required bandwidth specifications of the IEEE 802.11a/b/g standards. The measured peak antenna gains for the operating frequencies across dual WLAN bands are measured to be 3.4 and 1.0 dBi, respectively, with gain variations within 0.8 dBi. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 65–69, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20903

T-shaped monopole antenna with shorted L-shaped strip-sleeves for WLAN 2.4/5.8-GHz operation

A novel dual-broadband Y-shaped monopole antenna with dual shorted I-shaped strip-sleeves for 2.4/5.2/5.8-GHz wireless local area networks (WLANs) is proposed. Dual I-shaped strip-sleeves are introduced to be shorted with the ground plane to excite the upper resonant mode for operating at the 5.8-GHz band. The obtained impedance bandwidths reach about 48.5% for the 2.4-GHz band and 35.5% for the 5-GHz band, which meet the required bandwidth specifications of IEEE 802.11a/b/g standards. The measured peak antenna gains for the operating frequencies across dual WLAN bands are measured to be 4.7 and 4.9 dBi, respectively, with gain variations within 0.5 dBi.

Jeun-Wen Wu

Papers

Dual broadband design of rectangular slot antenna for 2.4 and 5 GHz wireless communication

2.4/5-GHz dual-band triangular slot antenna with compact operation

Novel dual-broadband rectangular-slot antenna for 2.4/5-GHz wireless communication

T-shaped monopole antenna with shorted L-shaped strip-sleeves for WLAN 2.4/5.8-GHz operation

Y-shaped monopole antenna with dual-broadband operation for WLAN