Jia-Yi Sze

Broadband CPW-Fed Circularly Polarized Square Slot Antenna With Lightening-Shaped Feedline and Inverted-L Grounded Strips

A novel design is described for a circularly polarized square slot antenna (CPSSA). Circular polarization (CP) operations can be attained using a lightening-shaped feedline protruded from the signal line of the feeding coplanar waveguide (CPW). The CP bandwidth can be significantly enhanced by implanting a pair of inverted-L grounded strips into the slot and adjusting the dimensions of the lightening-shaped feedline, whereas the impedance bandwidth can be greatly enlarged through tuning embedded vertical and horizontal stubs. The designed antenna was measured to exhibit a CP bandwidth of as high as 48.8%.

Circularly Polarized Square Slot Antenna With a Pair of Inverted-L Grounded Strips

This paper presents a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed. The proposed antenna features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW. Broadside circular-polarization (CP) radiation can be easily obtained using a simple design procedure. For the optimized antenna prototype, the measured bandwidth with an axial ratio (AR) of less than 3 dB is larger than 25% and the measured VSWR les 2 impedance bandwidth is as large as 52%.

Design of Circularly Polarized Annular-Ring Slot Antennas Fed by a Double-Bent Microstripline

A novel design of a circularly polarized annular-ring slot antenna is discussed. The circular polarization is attained through a newly proposed double-bent microstripline that feeds the antenna at two different positions. Several structural parameters were experimentally studied with care to establish a design procedure, which was subsequently drawn into a design flow chart. Validation was carried out using the antennas designed at 3.5 and 1.59 GHz. The measured 3-dB axial-ratio bandwidth (ARBW) for the former is 10.5% and for the latter, 10.0%, which is larger than the 8.5% 3-dB ARBW required by an Inmarsat application.

Design of a Compact Dual-Band Annular-Ring Slot Antenna

This letter aims at miniaturizing an annular-ring slot antenna that is suitable for the 2.4/5-GHz dual-band operations. The miniaturization purpose was achieved by embedding in the center patch of the antenna a pair of slots to excite three resonant modes. The resonant band of the first excited resonant mode was lowered from that of the unperturbed annular-ring slot antenna, whereas those of the second and third excited resonant modes were combined to form a wide upper operating band by appropriately adjusting the dimensions of the embedded slots. The proposed antenna proves to have very similar copolarization radiation patterns in its two operating bands and have enough antenna gains for practical applications.

Axial-Ratio-Bandwidth Enhancement of a Microstrip-Line-Fed Circularly Polarized Annular-Ring Slot Antenna

The design of a new microstrip-line-fed wideband circularly polarized (CP) annular-ring slot antenna (ARSA) is proposed. Compared with existing ring slot antennas, the ARSAs designed here possess much larger CP bandwidths. The main features of the proposed design include a wider ring slot, a pair of grounded hat-shaped patches, and a deformed bent feeding microstrip line. The ARSAs designed using FR4 substrates in the L and S bands have 3-dB axial-ratio bandwidths (ARBWs) of as large as 46% and 56%, respectively, whereas the one using an RT5880 substrate in the L band, 65%. In these 3-dB axial-ratio bands, impedance matching with VSWR ≤ 2 is also achieved.

Circularly Polarized Square Slot Antenna With a Largely Enhanced Axial-Ratio Bandwidth

A new easy-to-apply design procedure is proposed in this letter for constructing small wideband circularly polarized (CP) bidirectional and unidirectional square slot antennas. With an asymmetric T-shaped strip protruded from the signal line of the feeding coplanar waveguide (CPW) into the square slot, a reference antenna with a fractional 3-dB axial-ratio bandwidth (abbreviated as CPBW) of about 11% can be obtained. The proposed bidirectional CP slot antenna (BICPSA) can be modified from the reference antenna by stretching the left end of the T-shaped strip upward, by embedding a rectangular metal patch in the square slot, and by implanting a grounded metal strip from the right edge of the slot. The resulting BICPSA has a much larger CPBW of 39.1%, which is about 3.55 times that of the reference antenna. Finally, by placing a simple reflector underneath this BICPSA without changing its structural dimensions, one can obtain unidirectional radiation patterns with a greatly increased gain of 7.6 dBic, but with only a slightly decreased CPBW of 34.3%.

Design of Band-Notched Ultrawideband Square Aperture Antenna With a Hat-Shaped Back-Patch

A new square aperture antenna fed by a coplanar waveguide (CPW) is proposed for ultrawideband (UWB) applications. A corner-notched rectangular patch was printed on the backside of the substrate for enhancing the impedance bandwidth. Impedance matching for different ranges within the UWB can be easily obtained by adjusting the width and height of the back-patch, the distance from the back-patch to the lower edge of the aperture, and the size of the two notched corners in the back-patch. A rejected frequency band within the UWB was produced by embedding a pair of U-shaped slotlines in the back-patch. Measured and simulated results are presented along with simple design rules.

Miniaturized Dual-Band CPW-Fed Annular Slot Antenna Design With Arc-Shaped Tuning Stub

The design of a miniaturized dual-band CPW-fed annular slot antenna with arc-shaped tuning stub is proposed. The proposed feeding structure, which includes the arc-shaped tuning stub and a 50- transformer, is connected to the extremity of the CPW fed-line, achieving the dual-band input impedance matching. The return loss of the proposed design exhibits that two wide operating bands are over the bandwidths of 30.8% and 24.0%, respectively. By modifying the angle of the arc-shaped tuning stub, the first-higher order resonant mode can be shifted to the lower frequency band to combine with the fundamental mode of the annular slot, achieving the broadband operation with the bandwidth of 3048 MHz (78.4%). Moreover, the miniaturized design indicates an embedded strip is protruded from the ground plane into a slit, revealing the center frequencies of two resonant bands from 2752 to 1738 MHz (size reduction 60%) and 5022 to 3760 MHz (size reduction 44%), respectively. Two resonant bands of the prototype show the broadside radiation patterns with the maximum peak antenna gains of 3.8 dBi and 5.1 dBi, respectively.

Design of CPW-Fed Circularly Polarized Slot Antenna With a Miniature Configuration

This letter proposes the design of a new miniaturized circularly polarized (CP) printed square slot antenna (PSSA) fed by a coplanar waveguide (CPW). The characteristics of the design are that the CP operation and impedance matching can be independently achieved. The 3-dB axial-ratio band can be excited by protruding into the slot a halberd-shaped metal strip from the signal line of the CPW, whereas the VSWR ≤ 2 impedance band can be produced by implanting in the slot a grounded asymmetric inverted-T strip. Design rules established for the proposed antenna can effectively reduce the sizes of the ground plane and the slot.

A Dual-Broadband Circularly Polarized Slot Antenna for WLAN Applications

A novel dual-band, circularly polarized slot antenna with broadband characteristics in both axial ratio and impedance is developed. The radiations of antenna exhibit a left-hand circular polarization in the z > 0 direction and a right-hand circular polarization in the opposite direction at both the lower and upper bands. The measured impedance bandwidths are 55.33% (1.83-3.23 GHz) and 20.98% (4.99-6.16 GHz) while the axial ratio bandwidths are 32.14% (1.88-2.60 GHz) and 31.49% (4.95-6.80 GHz) at the lower and upper bands, respectively. In comparison to the recent works, the proposed antenna has a simpler structure, a more compact size, wider impedance bandwidths, and wider axial ratio bandwidths.