43 research outputs found

    Small Patch/Slot Antenna with 53% Input Impedance Bandwidth

    Get PDF
    A small microstrip patch/slot antenna, which achieves a very large bandwidth on a relatively thin substrate (about 0.01lambda0), is presented. The performance is achieved by employing a combination of annular-ring loading on the patch radiator and the use of a crossed-slot for miniaturisation. An additional ring-slot in the ground plane is used to produce the wideband characteristics of the antenna. Simulated and measured results indicate that a 53% fractional impedance bandwidth is achieved with respect to the centre frequency of 1.409 GHz and the size of the antenna is reduced by 50% compared to the conventional circular patch antenna with respect to a given frequenc

    Compact Annular-ring Embedded Circular Patch Antenna with Cross-slot Ground Plane for Circular Polarisation

    Get PDF
    A dual-frequency dual-circularly polarised patch antenna with wide beamwidth is proposed. The two-layer structure comprises circular patches with offset circular slots connected to rectangular slots. They provide orthogonal perturbations realising RHCP and LHCP for the lower and upper bands, respectively. The wide beamwidth is realised by extending the substrate beyond the groundplane. Measurements show a maximum beamwidth of 180deg and gains of 3.9 and 0.5 dBic for zenith and 10deg elevation, respectively, for the upper band. The measured beamwidth for the low band is 130deg with a maximum gain of 3.9 and -0.7 dBic for zenith and 10deg elevation, respectively. The axial-ratio is less than 3 dB in the hemisphere for elevations greater than 10deg for both bands

    Dual-frequency Dual-sense Circularly-polarized Slot Antenna Fed by Microstrip Line

    Get PDF
    A new design of a dual-frequency dual circularly-polarized slot antenna is presented. The dual-frequency is achieved using a single-layer microstrip-fed configuration coupled to a modified annular-slot antenna. The dual sense circular-polarization is obtained by four unequal linear slots which augment the annular slot. Experimental results show the proposed antenna has good circular polarization characteristics for both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The 10 dB return loss impedance bandwidths for the lower (RHCP) and higher (LHCP) bands are 26.7% and 11.3%, respectively. The 3 dB axial-ratio bandwidths are 6.1% and 6.0% with respect to 1.5 GHz (RHCP) and 2.6 GHz (LHCP), respectively

    Monofilar Spiral Slot Antenna for Dual-Frequency Dual-Sense Circular Polarization

    Get PDF
    A dual-band antenna with right-hand circular polarization for the first frequency and the counter polarization at the second frequency is realized with compact printed spiral slots. The coupled spiral slots are fed by a 50 ő© microstrip line. Dual-sense circularly-polarized performance is achieved by realizing oppositely-directed current rotation for the two frequency bands. A parametric study shows that the additional slot significantly improves the bandwidth for both frequency bands. Measured results show that the fractional impedance bandwidth is greater than 18% for both bands. The 3 dB axial-ratio bandwidths are 4.5% and 3.5% for the RHCP and LHCP bands, respectively

    Printed Circularly-Polarized Antenna with Ultra-Wide Axial-Ratio Bandwidth

    Get PDF
    A circularly polarised printed dipole-like antenna employing asymmetrical arms and an orthogonal slit in the ground plane is presented. It is fed by a stepped microstrip line which connects to the shorter arm. By utilising surface currents on the asymmetrical arms and the orthogonal feedline structure, circular polarisation is realised. Experimental and numerical data are in agreement and the measured results show a fractional impedance bandwidth of 41.3% (1.77‚Äď2.69 GHz) and a wide axial-ratio bandwidth of 38.4% (1.81‚Äď2.67 GHz)

    Miniaturized Annular Ring Loaded Patch Antennas

    Get PDF
    The proliferation of wireless communication systems has promoted the development of miniaturized antenna designs. Annular ring patch antennas are reported to reduce antenna size. In this paper, several novel compact probe-fed annular-ring microstrip patch antennas are presented. In order to reduce the antenna size and provide a suitable input impedance match, two techniques are employed; the insertion of strips into the annular ring and placing a cross-slot into the ground plane. The proposed annular-ring patch antennas with a cross-slotted ground plane yield a much smaller size for a given frequency and are easily matched to 50 Ohms. These novel patch antennas can effectively be reduced by about 55 percent in size compared to conventional annular-ring patch antennas. The antenna can be designed for single band circular-polarization, dual-band circular polarization, triple band, or wideband operation, depending on parameter selection. Some significant advantages are evident for these structures, such as the centre-frequency exhibiting weak dependence on the position of the feedpoint as well as compact size. Good circularly polarized properties and wide CP bandwidths are obtained for these compact antennas. The multiband versions can provide small frequency ratios. The optimized dimensions for four different type antennas are displayed

    A Cavity-Backed Spiral Slot Antenna with Wide Axial Ratio Beamwidth for GPS System

    Get PDF
    A monofilar spiral slot antenna with a cavity-backed reflector is described. presented, which can achieve the performance of the wide Axial Ratio beamwave for Global Positioning System GPS system. It comprises an arrangement of a single printed spiral slots fed by a 50 ő© microstrip line. By using cavity-backed covering the slot structure, a wide axial ratio beamwidth performance is achieved in the GPS L1 frequency. The angle with less than 3 dB axial ratio at 1.575 GHz in the YoZ plane is about 215 degree. The measured results show that the HPWB beamwidths at 1.575 GHz are 100 degree in the YoZ plane, respectively. The peak gain is 5.5 dBic

    Omnidirectional Circularly Polarized Patch Antenna with Post Manufacture Characteristic Refinement

    Get PDF
    We propose an omnidirectional circularly polarised planar microstrip patch antenna, in which both impedance bandwidth and circular polarization properties can be adjusted after antenna manufacture. This is done by appropriately tuning four adjustable capacitors, incorporated into the patches. To demonstrate the properties, the proposed antenna is tuned to the GPS L1 band and then re-tuned for Beidou/Galileo E2 band by only changing capacitors values. Design guidelines for such retuning are provided

    Directional Dual-Band Slot Antenna with Dual-Bandgap High-Impedance-Surface Reflector

    Get PDF
    A compact dual-band high-impedance-surface EBG structure is employed as a reflector for a dual-band annular-slot antenna. The reflector comprises an array of miniaturized EBG cells which utilizes square patches augmented by four S-shaped corrugated arms to reduce the resonant frequency of the proposed EBG structure. In order to broaden the bandwidth and adjust the frequency ratio for the dual-band EBG structure, a log-periodic spacing between the S-shaped strips is introduced. The combination of microstrip-fed annular slot and EBG reflector provides directional properties for both frequency bands with reduced size and low-profile
    corecore