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A small-size uniplanar printed antenna suitable for 2.4/5.2/5.8 GHz WLAN and 2.5/3.5/5.5 GHz WiMAX operations is presented. The antenna is a coupled-fed PIFA and shows a height of 9 mm and a width of 13 mm only, when mounted at the top edge of the display panel in the laptop computer. The multiband operation is achieved by using the coupling feed and further embedding a band-notching slit in the radiating arm of the PIFA. With the coupling feed, two wide operating bands can be generated at about 2.5 and 5.5 GHz for the PIFA. By further embedding the slit of length about a quarter-wavelength at about 4 GHz, a band-notching characteristic at about 4 GHz is obtained, which leads to an additional resonance at about 3.5 GHz and shows very small effects on the desired 2.5 and 5.5 GHz bands. This behavior results in successful excitation of an additional resonant mode for 3.5 GHz WiMAX operation. Hence, with no increase in the antenna size, three wide operating bands for covering all the desired operating bands of WLAN/WiMAX systems are achieved for the proposed PIFA. Details of the design considerations are presented, and results of the fabricated prototype are discussed. Index Terms--Band-notching, planar inverted-F antennas (PIFAs), printed antennas, WLAN antennas, WiMAX antennas.

A multiband printed monopole slot antenna promising for operating as an internal antenna in the thin-profile laptop computer for wireless wide area network (WWAN) operation is presented. The proposed antenna is formed by three monopole slots operated at their quarter-wavelength modes and arranged in a compact planar configuration. A step-shaped microstrip feedline is applied to excite the three monopole slots at their respective optimal feeding position, and two wide operating bands at about 900 and 1900 MHz are obtained for the antenna to cover all the five operating bands of GSM850/900/1800/1900/UMTS for WWAN operation. The antenna is easily printed on a small-size FR4 substrate and shows a length of 60 mm only and a height of 12 mm when mounted at the top edge of the system ground plane or supporting metal frame of the laptop display. Details of the proposed antenna are presented and studied. Index Terms--Internal laptop computer antennas, monopole slot antennas, multiband antennas, quarter-wavelength slot antennas, WWAN antennas.

A multiband folded loop chip antenna with a very small volume of 1 [cm.sup.3] (40 x 5 x 5 [mm.sup.3]) is presented. The antenna has a simple metal pattern comprising a folded loop strip anda tuning pad, and is especially suited for application in small-size mobile phones (groundplane length 60 mm only) for multiband operation. The metal pattern is attached on the surfaces of a foam base, and the first three resonant loop modes (0.5-, 1.0-, and 1.5-wavelength modes) of the antenna can be excited with good impedance matching by simply adjusting proper dimensions of the tuning pad and its location along the folded Ioop strip. The excited 0.5-wavelength mode forms as the antenna's Iower band at about 900 MHz for GSM operation, while the 1.0- and 1.5-wavelength modes are formed into a wide operating band at about 1900 MHz for the antenna's upper band to cover DCS/PCS/UMTS operation. Design considerations of the proposed folded loop chip antenna are described, and effects of the tuning pad on controlling the performances of the antenna are shown. Index Terms--Chip antennas, folded loop antennas, internal mobile phone antennas, mobile phone antennas, multiband antennas.

A simple shorted strip monopole with a coupling feed for penta-band WWAN (Wireless Wide Area Network) operation in the laptop computer is presented. With the coupling feed, which effectively compensates for the large inductive reactance of the antenna, a dual-resonance excitation for the antenna's lower band at about 1 GHz is achieved; the obtained bandwidth reaches 500 MHz, allowing the antenna to easily cover GSM850/900 operation. Also, a wide operating band is achieved for the antenna's upper band at about 1.9 GHz with a bandwidth of 540 MHz, hence easily covering GSM1800/1900/UMTS operation. With two wide operating bands achieved, the antenna occupies a thickness of 5 mm only and a small area of 9 x 79 [mm.sup.2] (not including the ground plane), making it very promising to be embedded inside the casing of the laptop computer as an internal WWAN antenna. The proposed antenna is studied in detail in this study. Index Terms--Coupling feed, internal laptop antennas, multiband operation, shorted monopole antennas, WWAN antennas.

A promising printed loop antenna is described that can be mounted in perpendicular to the top edge of the system circuit board of the mobile phone for penta-band operation. The antenna comprises a loop pattern printed on a thin FR4 substrate of small size 10 X 60 [mm.sup.2] and a perpendicular feeding portion printed on the narrow top ungrounded region of the system circuit board. Since the top ungrounded region is 4 mm in length only, the antenna is very low profile to the top edge of the ground plane on the system circuit board; that is, the antenna occupies a small volume inside the mobile phone housing and is suitable to operate as an internal antenna. In addition, the antenna generates two wide operating bands centered at about 900 and 1900 MHz to cover GSM850/900 and DCS/PCS/UMTS operations, respectively. Index Terms--Internal mobile phone antennas, multiband operation, penta-band operation, perpendicular feed, printed loop antennas.

A new internal multiband mobile phone antenna formed by two printed monopole slots of different lengths cut at the edge of the system ground plane of the mobile phone is presented. The antenna can generate two wide bands centered at about 900 and 2100 MHz to cover the GSM850/GSM900/DCS/PCS/UMTS bands and the 2.4-GHz WLAN band. Further, the antenna has a simple planar structure and occupies a small area of 15 x 40 [mm.sup.2] only. It is also promising to bend the antenna into an L shape to reduce its volume occupied inside the mobile phone. Good radiation characteristics are obtained over the two wide operating bands. Index Terms--Internal mobile phone antennas, mobile antennas, monopole slot antennas, multiband antennas, printed antennas.

A novel printed planar inverted-F antenna (PIFA) with two shielding strips to allow the antenna to be electromagnetic (EM) compatible with nearby conducting elements is presented. That is, the proposed printed PIFA can be placed in very proximity to nearby conducting elements with small or negligible effects on the antenna performances. This attractive feature is mainly because the antenna's possible EM fringing fields are suppressed by the two added shielding strips at the feed and end portions of the printed PIFA. Details of the proposed printed PIFA are described, and a design example for wireless local area network operation in the 2.4 GHz band is studied. Index Terms--Electromagnetic compatible (EMC) antennas, mobile antennas, planar inverted-F antennas (PIFA), printed antennas, wireless local area network (WLAN) antennas.

A novel dual-band printed loop antenna very promising for application in mobile phones as an internal antenna is presented. The antenna comprises an outer loop strip and an inner inverted-L strip connected to and enclosed by the outer loop strip. The antenna occupies a compact area of 15 x 50 [mm.sup.2] only, yet generating three resonant modes to form two wide bands at about 900 and 1800 MHz for the Global System for Mobile Communication/Digital Communication System operation. Detailed design considerations of the three excited modes are described in the paper. When a shielding metal case is placed close to the antenna, small effects on the antenna's impedance matching are seen, allowing compact integration of the antenna with nearby conducting elements or electronic components. The antenna is also found to result in small excited surface current distributions on the system ground plane of the mobile phone. This behavior is expected to lead to reduced user's hand effects on the radiation efficiency of the antenna. Index Terms--Dual-band antennas, mobile phone antennas, printed antennas, printed loop antennas.

A novel, ultrawideband (UWB) monopole antenna suitable to be mounted on the printed circuit board (PCB) of a wireless, universal, serial-bus (USB) dongle as an internal antenna is presented. The proposed antenna in the study is a U-shaped, metal-plate monopole antenna, easily fabricated from bending a simple metal plate onto a foam base of a compact size of 6 x 11 x 20 [mm.sup.3]. The antenna mainly comprises a pair of wide-ended radiating arms and a bevel-feed transition. When the antenna is mounted at the top portion of the PCB, one end of the radiating arm is also short-circuited to the system ground plane. With the proposed antenna structure, which can provide a very wide operating bandwidth of larger than 7.6 GHz, the antenna impedance bandwidth can easily cover the 3.1-10.6 GHz UWB band. Details of the antenna design are described, and experimental results of the constructed prototypes are presented and discussed. Index Terms--Antennas, internal antennas, ultrawideband (UWB) antennas, universal serial-bus (USB) dongle antennas.

A thin dual-band internal patch antenna for Global System for Mobile Communication, 890-960 MHz/Digital Communication System, 1710-1880 MHz (GSM/DCS) operation in a Personal Digital Assistant (PDA) phone is presented. The antenna can generate two wide resonant modes for GSM (890-960 MHz) and DCS (1710-1880 MHz) operation, yet it requires an air-layer substrate of thickness 4 mm only, which is among the thinnest internal mobile phone antennas that have been reported. The antenna's top patch comprises a resonant narrow strip supporting a longer resonant path for GSM operation and a resonant subpatch supporting a shorter resonant path for DCS operation. By including a suitable widened end portion for the narrow strip and a suitable tapered end portion for the subpatch, increased bandwidths for the proposed thin internal mobile phone antenna are obtained. Detailed design considerations of the proposed antenna are described. In addition, the user's hand effects on the performances of the proposed antenna are studied. Index Terms-GSM/DCS mobile phone antennas, internal antennas, internal mobile phone antennas, mobile antennas.

A single-feed reconfigurable square-ring patch antenna with pattern diversity is presented. The antenna structure has four shorting walls placed respectively at each edge of the square-ring patch, in which two shorting walls are directly connected to the patch and the others are connected to the patch via pin diodes. By controlling the states of the pin diodes, the antenna can be operated at two different modes: monopolar plat-patch and normal patch modes; moreover, the 10 dB impedance bandwidths of the two modes are overlapped. Consequently, the proposed antenna allows its radiation pattern to be switched electrically between conical and broadside radiations at a fixed frequency. Detailed design considerations of the proposed antenna are described. Experimental and simulated results are also shown and discussed. Index Terms--Patch antennas, pattern diversity, reconfigurable antennas.

A novel wideband monopole antenna integrated within the front-end module package for WLAN and/or WiMAX operation in the 5 GHz band for a mobile device is presented. The front-end module package mainly comprises a bent [pi]-shaped wideband monopole antenna for 5 GHz band operation and a shielding metal case for accommodating the associated module and circuitry. The antenna is integrated to the shielding metal case through short-circuiting. For practical applications, the proposed front-end module package is to be mounted at one of the corners of the system circuit board of the mobile device. In this case, the shielding metal case not only performs as part of the ground plane of the antenna, but also functions as a shielding metal block to shield the antenna from the undesired coupling with nearby electronic or conducting elements in the mobile device. The proposed design of the front-end module package with an embedded antenna is studied, and obtained results of the constructed prototypes are presented. Index Terms--Antennas, internal mobile antennas, integrated mobile antennas, wideband mobile antennas, WLAN antennas, WiMAX antennas.

A novel surface-mountable monopole chip antenna having an electromagnetic compatibility (EMC) property is presented. In addition to the radiating strip on the chip base of the antenna, a ground portion is added on the side surfaces of the chip base. The antenna ground portion is to be grounded to the system ground plane of the mobile device for practical applications. The antenna ground portion can function as an effective shielding wall between the antenna and the nearby electronic components in the device. In this case, the nearby components can be placed in close proximity to the antenna, with small effects on the antenna performances. That is, the proposed antenna is EM compatible with the nearby components. In addition, the proposed antenna is surface-mountable onto the system circuit board of the mobile device, which reduces the packaging cost of the device. The proposed antenna applied to a smart phone or Personal Digital Assistant (PDA) phone for WLAN operation in the 2.4 GHz band is studied in the paper. Index Terms--Antennas, chip antennas, electromagnetic compatibility (EMC) antennas, mobile antennas, wireless local area network (WLAN) antennas.

A novel internal dual-band patch antenna with a small thickness of 3 mm for application in Global System for Mobile Communication/Digital Communication System (GSM/DCS) mobile terminals such as the mobile phone or Personal Digital Assistant (PDA) phone is presented. The patch antenna occupies an area of 15 x 60 m[m.sup.2], with its top patch embedded with a simple T-shaped slit, which separates the top patch into two resonant paths to generate two resonant modes for 900/1800 MHz operation. Then, by extending a small portion of the top patch beyond the top edge of the system ground plane of the mobile terminal, the antenna can provide two wide bandwidths covering the GSM/DCS bands. The proposed antenna is experimentally studied, and effects of the extended top-patch portion and the ground-plane length on the obtained bandwidths are discussed. Index Terms--Antennas, dual-band antennas, Global System for Mobile Communication/Digital Communication System (GSM/DCS) mobile antennas, mobile antennas, mobile phone antennas, Personal Digital Assistant (PDA) phone antennas.

A novel patch antenna suitable to be applied in a mobile device as an internal antenna having an electromagnetic compatibility (EMC) property with nearby conducting elements is presented. The antenna is easily fabricated from a single metal plate and mainly comprises a top patch and an inverted-L vertical ground wall. Due to the presence of the inverted-L ground wall, which is perpendicular to the system ground plane of the mobile device, the possible fringing EM fields in the surrounding region of the antenna are suppressed. In this case possible coupling between the antenna and the nearby conducting elements is expected to be small, and thus degrading effects on the performance of the antenna are eliminated. A design example of the proposed antenna for Universal Mobile Telecommunication System (UMTS) 1920-2170 MHz operation in a mobile device is demonstrated and discussed. Index Terms--Antennas, electromagnetic compatibility (EMC) antennas, internal mobile phone antennas, mobile antennas, Universal Mobile Telecommunication System (UMTS) antennas.

A novel wireless local-area network (WLAN) chip antenna suitable to be mounted above the system ground plane of a mobile device is presented. The antenna in the study is easily fabricated from folding a single metal plate onto a foam base, and mainly comprises a short-circuited radiating strip and an antenna ground. The antenna ground occupies the bottom surface and two adjacent side surfaces of the foam base. When the antenna is mounted at the corner of the system ground plane, this antenna ground structure is expected to effectively reduce the antenna's possible fringing electromagnetic fields inside the mobile device. In this case, when the associated element such as the radio-frequency shielding metal case is placed under the proposed antenna, small or negligible variations in the antenna performance are obtained. Design considerations of the proposed antenna for WLAN operation in the 2.4 GHz band are described, and results of the constructed prototypes are presented. Index Terms--Antennas, chip antennas, mobile antennas, wireless local-area network (WLAN) antennas.

A novel design of feeding and short-circuiting an internal patch antenna for mobile phones is presented. The patch antenna comprises a simple rectangular patch that is fed through and short-circuited to a small ground plane (denoted as antenna ground here) which protrudes from the main or bottom ground of a folder-type mobile phone. With the presence of the small antenna ground, which can function as a shielding wall, the proposed antenna can be placed in close proximity to the RF shielding metal box in the mobile phone, with very small effects on the antenna performances. A design example of the proposed antenna for Universal Mobile Telecommunication System (UMTS) (1920~2170 MHz) operation is demonstrated. Experimental and simulated results are presented. Index Terms--Internal mobile phone antennas, mobile antennas, planar inverted-F antennas (PIFAs), shorted patch antennas, Universal Mobile Telecommunication System (UMTS) antennas.

A wide-band cylindrical monopole antenna is presented. The antenna has a simple structure consisting of an upper hollow cylinder and a lower cone. When choosing the cylinder and the cone to be of equal lengths (10 mm in this study with the ease of a 10-mm cylinder diameter), the antenna shows a wide operating bandwidth of about 8.8 GHz (about 1.8 to 10.6 GHz), making it easy to cover the UMTS (Universal Mobile Telecommunication System) band (1920~2170 MHz) and the 2.4/5.2/5.8 GHz WLAN (Wireless Local Area Network) bands for mobile/WLAN dual-mode operation of a mobile phone. Index Terms--Antennas, mobile antennas, mobile phone antennas.

A square planar metal-plate monopole antenna fed by using a novel trident-shaped feeding strip is presented. With the use of the proposed feeding strip, the square planar monopole antenna studied shows a very wide impedance bandwidth of about 10 GHz (about 1.4-11.4 GHz, bandwidth ratio about 1:8.3), which is larger than three times the bandwidth obtained using a simple feeding strip (about 1.5-3.3 GHz, bandwidth ratio about 1:2.3). In addition, the proposed feeding strip can be integrated with the square planar monopole, that is, the feeding strip and the square planar monopole together can be easily fabricated using a single metal plate, making the proposed antenna easy to construct at a low cost. Details of the experimental and simulation results for the proposed planar monopole antenna are presented and analyzed. Index Terms--Antennas, planar metal-plate monopole antenna, planar monopole antennas, ultrawide-band monopole antennas.

A novel dual-band flat-plate antenna with a shorted parasitic element for an internal laptop antenna for WLAN operation is presented. The proposed antenna is suitable to be integrated with the supporting metal frame for the display of the laptop and shows a low profile of 5 mm above the metal frame, thus making it easily embedded within the casing of the laptop as an internal antenna. Moreover, the proposed antenna can provide two separate impedance bandwidths of 190 MHz (about 8% centered at 2.4 GHz) and 2140 MHz (about 39% centered at 5.5 GHz), making it easily cover the required bandwidths for WLAN operation in the 2.4 GHz band (about 3.4% bandwidth required) and 5.2/5.8 GHz bands (about 13% bandwidth required). The proposed antenna is studied in detail in this study, and experimental and simulation results are presented. Index Terms--Antennas, dual-band antennas, flat-plate antennas, internal laptop antennas, WLAN antennas.

An omnidirectional planar antenna comprising two back-to-back folded dipoles printed on a dielectric substrate is presented. A constructed prototype suitable for WLAN operation in the 5-GHz hand, such as the 5.2-GHz (5150-5350 MHz) and 5.8-GHz (5725-5875 GHz) bands, is demonstrated. The constructed prototype shows a wide impedance bandwidth of larger than 1.1 GHz (about 20% centered at 5.5 GHz), and a stable antenna gain level of about 4.5 dBi, with small variations (< 2 dBi) for omnidirectional radiation, is obtained across the bandwidth. Details of the antenna design and the experimental results are presented. Index Terms--Folded dipole antennas, mobile antennas, omnidirectional antennas, planar antennas, printed antennas.

A planar dipole array antenna having good omnidirectional radiation in the azimuthal plane is presented. The planar dipole array antenna comprises two 1 x 2 dipole arrays arranged back to back and separated by a narrow rectangular ground plane, and is easily constructed by printing on both sides of a dielectric substrate. Prototypes of the proposed antenna for WLAN operation in the 2.4 GHz band (2400-2484 MHz) were constructed and studied. Good omnidirectional radiation with gain variations less than 2 dBi in the azimuthal plane has been obtained, and the measured maximum antenna gain for operating frequencies across the 2.4 GHz band is about 5.0-6.1 dBi. Effects of the ground-plane width and the array spacing on the performance of the proposed antenna are also studied. Index Terms--Antennas, array antennas, dipole antennas, omnidirectional dipole array antennas.

A novel single-feed broadband circularly polarized patch antenna is proposed. The proposed antenna has a simple structure, consisting of a corner-truncated square radiating patch, an L-shaped ground plane, and a probe feed. Through a via hole in the vertical ground of the L-shaped ground plane, the radiating patch is easily excited by a probe feed oriented in the same plane as the patch, and circular polarization (CP) radiation over a wide frequency range (> 10%) is achieved. Experimental results of a constructed prototype with the center operating frequency at about 2500 MHz showed that the antenna has an impedance bandwidth (1.5: 1 VSWR) of about 30%, a 3-dB axial-ratio CP bandwidth of about 10.4%, and a gain level of 8.5 dBi or larger within the CP bandwidth. In addition to the low cost of the proposed antenna due to its simple structure, the obtained CP performance is among the best that have been reported for single-feed single-element patch antennas, Index Terms--Broadband, circular polarization (CP), patch antenna, probe-fed.

In this communication, a novel design of the planar inverted-F antenna (PIFA) is proposed for the dual-band mobile phone application. To reduce the antenna size, the radiating patch is meandered and folded. The studies begin with a folded-patch PIFA that has two tunable resonant modes. Next, by loading three slits on the patch, the surface current path is meandered and the antenna length is reduced significantly. The IE3D simulation software is employed for optimizing the design parameters, and the simulation results in general agree with the measured data. Results also show that, the excitation of the 900 and 1800 MHz resonant modes can be achieved for the proposed antenna with a small volume of 24 X 10 X 7.2 [mm.sup.3]. Radiation patterns for both resonances are measured and shown. The maximum antenna gain is estimated to be 2.5 dBi for both 900/1800 bands operations. Index Terms--Dual-band planar antenna, planar inverted-F antenna (PIFA).

A novel and simple printed dual-band double-T monopole antenna is proposed. The antenna comprises two stacked T-shaped monopoles of different sizes, which generate two separate resonant modes for the desired dual-band operations. The proposed antenna has a low profile and can easily be fed by using a 50 [OMEGA] microstrip line. Prototypes of the proposed antenna designed for WLAN operations in the 2.4 and 5.2 GHz bands have been constructed and tested. Good radiation characteristics of the proposed antenna have been obtained. Effects of varying the monopole dimensions and the ground-plane size on the antenna performance have also been studied. Index Terms--Antennas, dual-band antennas, monopole antennas, printed antennas.

A new design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide (CPW) is proposed and experimentally studied. The proposed broadband circular polarization (CP) operation is achieved by protruding a T-shaped metallic strip from the ground plane toward the slot center and feeding the square slot antenna using a 50-[ohms] CPW with a protruded signal strip at 90[degrees] to the T-shaped strip. Experimental results of constructed prototypes show that the obtained 3-dB and 1-dB axial-ratio bandwidths can reach as large as 18% and 13%, respectively. The proposed antenna also has a peak antenna gain of about 4 dBi, with gain variations less than 1 dBi for frequencies within the CP bandwidth. Index Terms--Circular polarization, coplanar waveguide (CPW)-fed, printed square slot antenna.

A novel compact design for achieving dual-band dual-polarized radiation suitable for applications in the 900/1800-MHz cellular systems is presented. The proposed antenna consists of a rectangular ring patch (for the 900-MHz operation) and a notched rectangular patch (for the 1800-MHz operation), which are printed on the same layer, and each patch is aperture-coupled by two H-shaped coupling slots to generate two orthogonal linearly polarized waves. By further incorporating a properly designed feed network, the proposed antenna shows good port decoupling of less than -39 dB and -34 dB for dual linear polarizations in the 900- and 1800-MHz bands, respectively. Details of the antenna design and experimental results are presented. Index Terms--Antennas, dual-band antennas, dual-polarized antennas, patch antennas.

A novel planar monopole antenna with a very low profile (antenna height less than 0.04 times the operating wavelength in the free space) and capable of multiband operation is proposed. The proposed antenna has a planar rectangular radiating patch in which a folded slit is inserted at the patch's bottom edge. The folded slit separates the rectangular patch into two subpatches, one smaller inner subpatch encircled by the larger outer one. The proposed antenna is then operated with the inner subpatch resonating as a quarter-wavelength structure and the outer one resonating as both a quarter-wavelength and a half-wavelength structure. The proposed antenna, 12 mm in height and 30 mm in width has been constructed, and the obtained bandwidths cover the global system for mobile communication (890-960 MHz), digital communication system (1710-1880 MHz), personal communication system (1850-1990 MHz), and universal mobile telecommunication system (1920-2170 MHz) bands. Details of the proposed design and obtained experimental results are presented and discussed. Index Terms--Antennas, mobile antennas, monopole antennas, multifrequency antennas.

A new design of a broad-band probe-fed patch antenna with a W-shaped ground plane is presented. The W-shaped ground plane is obtained by bending the conventional planar ground plane into an inverted V-shape, seen in the resonant direction of the patch antenna and then adding proper flanges at the two straight edges of the bent ground plane. The proposed design is applicable to the patch antenna with a planar radiating patch with a thin-air substrate. With the use of the proposed W-shaped ground plane, the required probe-pin length in the substrate remains to be small, although the effective substrate thickness is significantly increased, resulting in a much wider operating bandwidth. Also, by choosing proper dimensions of the W-shaped ground plane, the antenna gain for frequencies over the obtained wide bandwidth is enhanced, compared to the conventional patch antenna with a planar ground plane. In addition, the cross polarization is also reduced for the proposed design and the cross-polarization level (XPL) in the H-plane pattern can even be better than that of a conventional probe-fed patch antenna with a thin air substrate. Index Terms--Broad-band antennas, ground plane, microstrip patch antenna.