Chien-Yuan Pan

Broadband CPW-Fed Circularly-Polarized Slot Antenna With an Open Slot

A novel broadband CPW-fed circularly-polarized slot antenna with an open slot is presented. The broadband circular polarization can be achieved simply by opening the radiation slot at the lower left of slot. From the experimental results, the 3-dB axial-ratio bandwidth can reach as large as 1000 MHz (27% relative to the center frequency of 3700 MHz) which can cover the 3.3-3.8 GHz WiMAX band. In addition, the proposed design has the VSWR ≤ 2 impedance bandwidth of 5330 MHz (111% relative to the center frequency of 4795 MHz) which can cover the 2-6 GHz WiMAX band. The proposed antenna also has a peak antenna gain of about 5.3 dBic and gain variations can be less than 1 dBic for frequencies within the CP bandwidth.

Miniature Folded Patch GPS Antenna for Vehicle Communication Devices

A novel miniature folded square patch antenna is proposed and developed for Global Positioning System (GPS) receivers. Four different lengths of meander strips connected to the four edges of the square patch of a single coaxial-feed square patch antenna are folded to obtain a circularly polarized antenna. Properly positioning the coaxial feed on the square patch excites two orthogonal resonant modes with a 90 ° phase difference and achieves a pure circular polarization. Conventional antennas for roof-mounted vehicle communication devices use commercially available ceramic corner-truncated patches whereas the proposed GPS antenna is designed to use a less expensive and more compact FR4 patch. Experiments also showed that mounting the proposed GPS antenna in different locations on the roof of a vehicle had little effect on circular polarization radiation. The fabricated prototype revealed an impedance bandwidth of 2.1% and a 3-dB axial-ratio bandwidth approximating 0.76% at a GPS frequency of 1575 MHz. Experiments confirmed that the characteristics of the proposed antenna were consistent with the simulation results.

Printed Arrow-shaped Self-Complementary Antenna for Wlan/wimax Applications

The paper presents a new and simple printed microstriplinefed self-complementary antenna for the WLAN and WiMAX applications. This antenna is composed of an arrow-shaped self-complementary configuration (ASSC) and a simple 50Ω microstrip feedline. The proposed antenna has two resonant structures, one of which is a half-arrow-shaped radiating monopole with a microstrip feedline, and the other is a complementary counterpart open slot on the extended ground plane. The ASSC mainly excites two resonant modes at 2.6 GHz and 3.8 GHz, respectively, in order to achieve wideband operation. The measured results show that the impedance bandwidth for 10 dB return loss is 4.11 GHz (2.24–6.35 GHz), which corresponds with a fractional bandwidth of 95%, and it can simultaneously cover WLAN and WiMAX bands. The measured and simulated radiation patterns and gains exhibit reasonable characteristics. In addition, the proposed antenna has a simple and compact size of 30 × 30 × 1.6 mm3.

Realization of compact and broadband performances using the microstrip-line-fed slot antenna

The printed microstrip-line-fed broadband slot antenna is investigated in this paper. With the use of the offset microstrip feed line and the corner-truncated protruded ground plane, the bandwidth enhancement and the size reduction for the proposed slot antenna can be obtained. From experimental results, the measured impedance bandwidth, with a 10-dB return loss, can be up to 5210 MHz (108.2%) which is about 2.67 times of a conventional printed microstrip-line-fed rhombus slot antenna. Under the use of the protruded ground plane, antenna size can be reduced by about 52%. By selecting proper parameters of the proposed slot antenna, it can provide with the wireless communication services operating at WLAN/WiMAX bands.

COPLANAR PRINTED MONOPOLE ANTENNA USING COAXIAL FEEDLINE FOR DTV APPLICATION

This article presents a coplanar printed monopole antenna for digital television (DTV) in the UHF band (470{862MHz) application. The antenna structure consists of a meander loop monopole for radiation, a step-shaped ground plane for impedance matching, and a 50-› mini coaxial feedline for excitation. The meander loop monopole and step-shaped ground plane are printed on the same side of a substrate with an area of 15 £ 170mm 2 . The measured impedance bandwidth for 2.5:1 voltage standing wave ratio (VSWR) is 550MHz (465{1015MHz, 74%), covering the DTV band. In addition, the proposed antenna shows a real reception performance on a notebook computer. The reception results for audio and video signals exhibit stable characteristics.

Microstrip-line-fed circularly-polarized circular slot antenna with a spur slot

A new Microstrip-line-fed circularly-polarized circular slot antenna with a spur slot is presented. The proposed circularly-polarized (CP) operation can be achieved simply by embedding the spur slot along the circumference of circular slot. From the experimental results, the 3-dB axial-ratio bandwidth can reach as large as 105 MHz (4.3% relative to the centre frequency of 2447.5 MHz) for the application as a 2.45-GHz RFID reader.

Printed i-shaped monopole antenna with circular conductor-backed plane for WLAN operations

This paper demonstrates a new and simple dual-band design for printed monopole antennas. The design basically consists of a stepped-width (I-shaped) radiating monopole element fed by a microstrip feedline with a circular conductor-backed plane. The configuration is designed to achieve the 2.4 GHz and 5.2 GHz dual-band operation for WLAN applications. Measured results show that impedance bandwidths for the antenna design configuration sufficiently cover both 2.4 GHz and 5.2 GHz WLAN bands with radiation patterns similar to a typical monopole-antenna radiation pattern.

Planar band-notched ultra-wideband monopole antenna using single open-circuited stub

This paper presents a novel printed monopole antenna with band-notched characteristics. The proposed antenna consists of a sector radiating monopole and a microstrip feedline connected in shunt a quarter wavelength open-circuited stub. In order to achieve band-notched performance, using a single open-circuited transmission line (a stub) of length quarter wavelength, connected in parallel with the microstrip feedline at a certain distance from the monopole antenna. The input impedance of the quarter wavelength opencircuited stub is nearly zero impedance leads to the great reflection and impedance mismatching at the notch frequency, which causes the antenna to be nonresponsive and occurs band-notched phenomenon. This design technique is very suitable for other printed antennas.

CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

Abstract A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894–1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910–970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

Wideband microstrip-line-fed circularly polarized slot antenna with open slot structure

A new wideband circularly polarized (CP) slot antenna with open slot structure using a microstrip-line for feeding is presented. The proposed antenna consists of an open C-slot with a straight slit on the ground plane, and a microstripline with a semi-circle-shaped patch on the other side of the substrate. The antenna size is reduced by about 35% compared with the circular slot antenna. By using the semi-circle-shaped patch to disturb the magnetic current distribution on the open C-slot, a wider CP bandwidth can be achieved. The measured results show that the proposed antenna can provide a 3 dB axial ratio (AR) bandwidth of 40% (4.1-6.2 GHz) and a 10 dB return loss impedance bandwidth of 107% (2.3-7.6 GHz).