Hao-Chun Tung

Broadband dual-polarized aperture-coupled patch antennas with modified H-shaped coupling slots

This paper presents a new design of aperture-coupled patch antennas with modified H-shaped coupling slots for achieving dual-polarization radiation with high isolation over a wide bandwidth. By using the proposed coupling slots, whose two upper side arms are bent inward with a proper angle, the isolation between the two feeding ports of the patch antenna can. greatly be improved, compared to the case with conventional H-shaped coupling slots. Also, when using a pair of modified H-shaped coupling slots for each feeding port, the isolation can further be improved; a high degree of isolation ( 20 dB) for the two polarizations can be achieved. Details of the proposed design and experimental results are presented and discussed.

An inverted U-shaped patch antenna for compact operation

By using a novel inverted U-shaped radiating patch in place of the conventional planar patch, compact operation of air-substrate patch antennas is presented. The inverted U-shaped patch is formed by adding two downward rims at the two radiating edges of a planar rectangular or square patch. And owing to the added rims, the excited patchs surface current paths are lengthened, which effectively lowers the antennas resonant frequency and results in large antenna size reduction (>50%). The proposed compact design has been successfully applied to air-substrate patch antennas fed by an aperture-coupled feed. In addition to large size reduction obtained, the proposed antenna with an air-substrate thickness about 5% the wavelength of the center operating frequency can have an impedance bandwidth (10-dB return loss) greater than 9%, a peak antenna gain of about 6.4 dBi, and good broadside radiation patterns with cross-polarization levels better than 20 dB in principal planes.

Dual-band inverted-L monopole antenna for GSM/DCS mobile phone

Introduction Two promising dual-band designs of the inverted-L monopole antenna loaded with a meandered wire or a helix for applications in GSM/DCS dual-band mobile phones are presented. In the proposed designs, the inverted-L monopole is operated as a quarter-wavelength structure for 1800 MHz operation. The meandered wire or the helix [ 11 is also operated as a quarter-wavelength structure, and however, is for 900 MHz operation. In addition to two separate wide bandwidths obtained for the proposed designs, the antenna’s height from the ground plane is only about 14 mm or 4.2% of the wavelength at 900 MHz. This low-profile advantage makes the proposed designs very promising to be integrated within the mobile phone housing, similar as the design in [2], leading to no protruded antenna in appearance for mobile phones. In addition, the proposed antennas have a simple structure and are easy to construct with low cost. No extemal matching circuit is also required for the proposed antennas.

A compact patch antenna with an inverted U-shaped radiating patch

We propose a new compact design of using an inverted U-shaped radiating patch to achieve a lower fundamental resonant frequency for a patch antenna with a thick air substrate. The proposed design is very suitable for applications with air-substrate patch antennas, and in the present study, it has been found that a significant lowering of the resonant frequency of about 32% can be achieved for the patch antenna with an air-substrate thickness about 5% of the wavelength of the center operating frequency. When the patchs aspect ratio and desired operating frequency are fixed, this lowering in resonant frequency corresponds to an antenna size reduction of about 54%. Also, since the lengthening of the effective patchs surface current paths is due to the additional downward paths in the added rims, different from the designs with meandered patches, relatively very small perturbation on the excited surface current distribution in the radiating patch is expected. This suggests that it is possible for the radiation characteristics of the proposed antenna to be as good as those of a regular patch antenna with a planar radiating patch.

Integrated rectangular spiral monopole antenna for 2.4/5.2 GHz dual-band operation

Introduction To achieve dual-band operations in WLAN (wireless local area network, 2400-2484 MHz) and HIPERLAN (high-performance radio local area network, 5150-5350 MHz) systems, printed monopoles in the form of an inverted-F structure [ I ] and an F-shaped structure [2] have been implemented. In these two designs, two different resonant paths are utilized to obtain the desired dual-frequency operation at 2.4 and 5.2 GHz. The latter design is also integrated on a small region of a microwave substrate or a system circuit board, thereby leading to a smaller realty space required for accommodating the printed monopole. In this article, we demonstrate another promising design using a rectangular spiral printed monopole fro achieving 2.4 and 5.2 GHz dual-band operations. In this design, the monopoles first two resonant frequencies are tuned to be around the desired 2.4 and 5.2 GHz; that is, a single resonant path is used for obtaining the dual-band operation, which makes the proposed design with a more compact realty space required.

Multiband slot antenna with passive components for 4G application

With the shunted passive components, a simple structure, multiband slot antenna is proposed. Shunted passive components act as different boundary condition at different frequency. Properly choosing the value of passive components and the location of the shunted passive components, the proposed antenna can generate three resonate mode to cover LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS, LTE2300, and LTE2500 operating bands for 4G system applications. Results of measurement for return loss, current distribution, radiation pattern and antenna Gain of proposed antenna are presented and discussed.

A compact dual-polarized aperture-coupled patch antenna for GSM1800 cellular system operation

In this paper, we present a compact design of a dual-polarized aperture-coupled patch antenna suitable for application in the GSM1800 cellular system (1710 to 1880 MHz). The proposed antenna has a square radiating patch of dimensions 50 /spl times/ 50 mm/sup 2/, which is only about 0.69 times that of the conventional design using a simple square patch. With the antenna size reduction achieved, good dual-polarized performances have also been obtained for the proposed antenna. Port decoupling better than -37.3 dB and good radiation characteristics for frequencies across the operating bandwidth have been obtained. Cross polarization lower than -20 dB and a peak antenna gain of about 7 dBi have also been observed.