Chih-Hua Chang

Printed

A small-size printed planar inverted-F antenna (PIFA) operated at its one-eighth wavelength (lambda/8) mode as the fundamental resonant mode for achieving WWAN (wireless wide area network) operation in the mobile phone is presented. The proposed PIFA has a simple structure of comprising two radiating strips of length about lambda/8 at 900 MHz and is fed using a coupling feed. Compared to the traditional PIFA using a direct feed, the coupling feed greatly decreases the very large input impedance seen at the lambda/8 mode for the traditional PIFA and results in successful excitation of the lambda/8 mode for the proposed PIFA. Two lambda/8 modes are generated by the two radiating strips and occur at close frequencies at about 900 MHz to form a wide lower band to cover GSM850/900 operation. The two radiating strips also generate two higher-order modes or lambda/4 modes at about 1900 MHz to form a wide upper band for GSM1800/1900/UMTS operation. Penta-band WWAN operation is hence achieved, yet the proposed PIFA only occupies a small printed area of 15times31 mm2 or 465 mm2 on the system circuit board of the mobile phone, which is about the smallest for the internal uniplanar printed antenna capable of penta-band operation that have been reported. Details of the proposed PIFA are presented. The specific absorption rate (SAR) and hearing aid compatibility (HAC) results for the proposed PIFA are also analyzed.

\lambda/8

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 antennas 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 antennas 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 times 79 mm2 (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.

-PIFA for Penta-Band WWAN Operation in the Mobile Phone

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.

Internal Coupled-Fed Shorted Monopole Antenna for GSM850/900/1800/1900/UMTS Operation in the Laptop Computer

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 antennas 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.

Surface-mountable EMC monopole chip antenna for WLAN operation

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 antennas 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.

WLAN chip antenna mountable above the system ground plane of a mobile device

A novel printed antenna for digital television (DTV) signal reception in the portable media player (PMP) device is presented. The proposed is suitable to be integrated with the system ground plane of the PMP device. The proposed antenna comprises a driven strip and a coupled strip short- circuited to the system ground plane of the PMP device. With the integration of the proposed antenna with the system ground plane, a resonant loop path is formed and a one-wavelength resonant loop mode is generated. Further, in between the driven and coupled strips, there is a lengthened coupling gap which effectively lowers the antennas one-wavelength resonant loop mode and leads to the excitation of a half-wavelength resonant loop mode. The two resonant loop modes are formed into a wide operating band to easily cover the DTV signal reception in the 470 ~ 806 MHz band. In addition, owing to the antennas compact size and simple structure, the proposed antenna is promising to be concealed within the housing of the PMP device as an internal antenna. A design example is demonstrated, and obtained results are presented and discussed.

Printed PIFA EM Compatible With Nearby Conducting Elements

A planar λ/8-PIFA with a coupling feed for achieving GSM850/900/1800/ 1900/UMTS operation in the mobile phone has been proposed and studied. With penta-band operation obtained for WWAN communication, the proposed λ/8-PIFA occupies a small area of 7 × 40 mm2 on an inexpensive 1.6-mm thick FR4 substrate. The compact size of the proposed PIFA also makes it promising to be embedded inside the casing of the mobile phone to operate as an internal antenna. In addition, two λ/8 modes are excited at close frequencies around 900 MHz to form a wide operating band for the antennas lower band by using a common coupling feed. Further, two higher-order modes (λ/4 modes) are also successfully excited at close frequencies around 1900 MHz to provide a wide operating band for the antennas upper band. The obtained wide lower and upper bands allow the proposed PIFA to cover GSM850/900/1800/1900/UMTS penta-band operation for WWAN communication. The proposed planar λ/8-PIFA is promising for practical application in the mobile phone for WWAN communication.

Integrated printed antenna for DTV signal reception in the portable media player

A small-size reconfigurable coupled-fed loop antenna for multi-band LTE/WWAN mobile handset is presented. The antenna volume is 5 × 10 × 30 mm^3 only, while the protruded ground has a width of 30 mm for mounting electronic components. The proposed antenna is consisted of a loop strip and a driven strip. Through the driven strip capacitively coupled to the loop strip, the antenna can generate a quarter-wavelength loop resonant mode to form the antennas lower band to cover the GSM850/900 bands (824~960 MHz). The simple driven strip is also an efficient radiator to excite a resonant mode for the antennas upper band to cover the GSM1800/1900/WCDMA Band 1 bands (1710~2170 MHz). Moreover, when the chip inductor connected to the loop strip has been adjusted from 0 to 12 nH, the antennas lower band can be shifted to lower frequency and cover the LTE Band 17 band (704~746 MHz). This tunable technique can allow the loop antenna to cover more operating bands without adding the antenna volume. Detailed operating principle and performances of the proposed antenna are discussed in the article.

Penta-band one-eighth wavelength PIFA for internal mobile phone antenna

A simple printed monopole slot antenna for penta-band wireless wide area network operation in the mobile phone is presented. The monopole slot has an area of 140 mm2 only and is embedded near the bottom edge of the system ground plane of the mobile phone. By adding longer parasitic shorted strip connected orthogonal to the bottom corner edge of the system ground plane, good excitation of the monopole slot antenna at its fundamental (quarter-wavelength) and high-order resonant modes can be achieved. The shorter parasitic shorted strip is disposed near the monopole slot and contributes additional resonant mode to the antenna. The excited resonant modes form two wide operating bands to cover the GSM850/900 operation (824~960 MHz) and GSM1800/1900/UMTS operation (1710~2170 MHz). Detailed operating principle of the proposed antenna is discussed in the article.

Compact Tunable Coupled-fed Loop Antenna for Multi-band LTE/WWAN Operation in the Mobile Phone

A shorted monopole antenna with a coupling feed for penta-band WWAN operation has been proposed. The antenna has a simple structure and is promising to be embedded inside the casing of the laptop computer to operate as an internal WWAN antenna. Owing to the coupling feed used in the proposed antenna, a dual-resonance excitation centered at about 1 GHz for the antennas lower band and a wide operating band centered at 1.9 GHz for upper band have been obtained. The operating bandwidths of the antennas lower and upper bands cover GSM850/900/1800/1900/UMTS operation. Good radiation characteristics for frequencies over the operating bands have also been obtained. The proposed antenna is promising for practical applications as an internal WWAN antenna in the laptop computer.