Yun-Wen Chi

Quarter-Wavelength Printed Loop Antenna With an Internal Printed Matching Circuit for GSM/ DCS/PCS/UMTS Operation in the Mobile Phone

A small-size printed loop antenna with an internal printed matching circuit capable of GSM/DCS/PCS/UMTS operation in the mobile phone is proposed. The antenna comprises an 85-mm long folded loop strip and an internal printed matching circuit encircled therein and formed by a coupling strip and an inductive strip. The loop strip is excited by the coupling strip to generate a 0.25 lambda resonant mode at about 900 MHz for GSM operation. For the inductive strip, it effectively causes a wideband higher order mode at about 1900 MHz for DCS/PCS/UMTS operation. Further, the antenna shows a uniplanar structure and requires a very small printed area of 170 mm2 on the system circuit board of the mobile phone, making it easy to fabricate at low cost. Details of the proposed antenna and its radiation performances including the SAR (specific absorption rate) results are studied.

Compact Multiband Folded Loop Chip Antenna for Small-Size Mobile Phone

A multiband folded loop chip antenna with a very small volume of 1 cm3 (40 times 5times 5 mm3) is presented. The antenna has a simple metal pattern comprising a folded loop strip and a 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 loop strip. The excited 0.5-wavelength mode forms as the antennas lower 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 antennas 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.

Internal Compact Dual-Band Printed Loop Antenna for Mobile Phone Application

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 times 50 mm2 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 antennas 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 users hand effects on the radiation efficiency of the antenna

Broadband Printed Dipole Antenna With a Step-Shaped Feed Gap for DTV Signal Reception

A broadband printed dipole antenna capable of generating a wide operating band for digital television signal reception in the 470-806 MHz band is presented. The antenna is of a rectangular shape of width 20 mm and length 227 mm , and comprises two asymmetric radiating portions of arm 1 and arm 2 separated by a step-shaped feed gap with its one open end at the center of antennas one long side edge and the other open end at about /4 away from the center of the opposite long side edge. The antenna can generate two adjacent resonant modes to form a wide operating band of larger than 50% in 2.5:1 VSWR bandwidth, which is much wider than that of the corresponding conventional center-fed dipole antenna.

Wideband printed dipole antenna for DTV signal reception

A novel printed dipole antenna capable of generating a wide operating band for digital television (DTV) signal reception in the 470 ~ 806 MHz band is presented. The antenna is of a rectangular shape and has a size of 20 times 227 mm2, and the antenna comprises two asymmetric radiating portions of arm 1 and arm 2 separated by a step-shaped feed gap with its one open end at the center of antennas one long side edge and the other open end at about L/4 away from the center of the opposite long side edge. By the use of the step-shaped feed gap, the proposed antenna can generate two adjacent resonant modes to form a wide operating band of larger than 50% in 2.5:1 VSWR bandwidth, which is much wider than that of the corresponding conventional center-fed dipole antenna with a straight feed gap. The antennas first resonant mode is operated as a 0.5-wavelength mode controlled by the antenna length L, while the second resonant mode is a 1.0-wavelength mode controlled by the total effective length of arms 1 and 2, which is about 1.25L in the proposed design. Detailed design considerations and radiation characteristics of the two excited resonant modes for broadband operation of the proposed dipole antenna are discussed in the paper.

Small-size multiband folded loop antenna for small-size mobile phone

Recent studies showed that the loop antennas are promising candidates for multiband operation in the mobile phones [1]-[3]. These promising loop antennas can be implemented by directly printing on the system circuit board of the mobile phone [1] or fabricated by cutting from a metal plate/strip or printing on an FR4 substrate and then mounted above the system circuit board [2], [3]. In this paper, we present a multiband loop antenna with a very small occupied volume of 1 cm3 (40 times 5 times 5 mm3) only, yet capable of GSM (890~960 MHz), DCS (1710~1880 MHz), PCS (1850~1990 MHz) and UMTS (1920~2170 MHz) operation. The occupied volume of 1 cm3 is among the smallest in the conventional internal multiband mobile phone antennas [4]. The proposed loop antenna comprises a folded uniform loop strip attached on a foam base and a tuning pad connected to the loop strip. Good excitation of the antennapsilas first three resonant modes (0.5-, 1.0- and 1.5-wavelength modes) to cover GSM/DCS/PCS/UMTS operation can be obtained. Moreover, the proposed loop antenna is especially suited for application in the small-size mobile phone with a small groundplane length of 60 mm only. This behavior is owing to that the excited surface currents of the 0.5-, 1.0 and 1.5-wavelength loop modes on the system ground plane are smaller than that of the conventional internal mobile phone antennas such as the PIFAs. In this case, less dependence of the performances of the proposed antenna on the length of the system ground plane can be expected.

Printed dual-band loop antenna for mobile phone application

In this paper, we present a novel printed loop antenna for mobile phone applications. It occupies an area of 15 times 50 mm only, yet providing two wide operating bands for GSM (Global System for Mobile Communication, 890 ~ 960 MHz) and DCS (Digital Communication System, 1710 ~ 1880 MHz) operation. Detailed design considerations of the antenna and the mechanisms of the mode excitation will be described in this study.

Printed folded slot antenna for internal multiband mobile phone antenna

In this paper, we demonstrate that the slot antenna is also very promising for application in the mobile phone. The proposed slot antenna in this study occupies a compact area of 21 x 45 mm2 only and is suitable to be printed on the system circuit board of the mobile phone. The proposed slot antenna can also generate two wide operating bands, with the lower band covering GSM operation and the upper band covering DSC/PCS (Personal Communication System, 1850~1990 MHz)/UMTS (universal mobile telecommunication system, 1920~2170 MHz) operation. Detailed design considerations of the proposed slot antenna are described in the paper. The proposed antenna is also fabricated and tested. Results of the fabricated prototype are presented and discussed.

Quarter-wavelength printed loop antenna for GSM/DCS/PCS/UMTS operation

A folded printed loop antenna with small length (62 mm) and occupied area (< 100 mm2) and capable of GSM/DCS/PCS/UMTS operation in the mobile phone has been proposed. The loop antenna can operate at its 0.25lambda mode as the lower band for covering GSM operation, and its 0.5lambda and 1.0lambda modes can also be generated to form the upper band for covering DCS/PCS/UMTS operation. The successful excitation of the three resonant modes is obtained by incorporating a simple series LC matching circuit. With proper selection of the series capacitor and inductor (0.47 pF and 13 nH here) in the matching circuit, the large inductive reactance of the 0.25lambda mode of the loop antenna can be compensated, and good impedance matching over the 0.5lambda and 1.0lambda modes can also be achieved. Antenna gain for frequencies over the operating bands has also been shown.

Quarter-wavelength printed loop antenna with an internal printed matching circuit for WWAN operation in the mobile phone

It is a trend that the mobile phone employs several system modules for a variety of applications. The internal antennas for different system modules are usually required to be mounted in close proximity inside the limited space of the mobile phone. As a result, the internal antennas with a decreased size are hence attractive and usually demanding for practical applications. Recently, the loop antennas are found attractive to multiband mobile phone applications [1]–[3]. It is shown that the loop antennas can be formed by a narrow metal strip folded into a compact configuration and still show a wideband or multiband operation for WWAN operation. On the other hand, to further reduce the internal antenna size, several designs using an external matching circuit to widen the operating bandwidth have also been reported [4]–[6]; however, the studied matching circuit usually works for single band only. In this paper, we demonstrate a small-size printed loop antenna with an internal printed matching circuit operating at its 0.25-wavelength resonant mode as the fundamental mode for mobile phone application. The proposed printed loop antenna has a folded loop metal strip of length 85 mm (about 0.25λ at 900 MHz) printed on the top no-ground portion of the system circuit board. The printed matching circuit is encircled by the loop strip and comprises a coupling strip and an inductive strip. The coupling strip effectively compensates for the large inductive reactance of the input impedance of the antennas 0.25λ mode, while the inductive strip has constructive effects on improving the impedance matching of the antennas dual-resonant 0.5λ mode. Note that the internal printed matching circuit applied here allows the excitation of a much lower first resonant mode (0.25λ mode) for the proposed loop antenna in the mobile phone [6].