Lei Bian

Broadband Circularly Polarized Annular-Ring Microstrip Antenna

A wideband circularly polarized (CP) annular-ring patch antenna with two proximity-coupled L-probe feeds orientated to have phases of 0deg and 90deg, using a broadband 90deg hybrid feed, is proposed. It is found that the current distribution for CP operation can be improved by cutting a smaller concentric circular slot on the original larger circular patch to form an annular-ring patch. With such an arrangement, the proposed antenna delivers a wider axial ratio (AR) bandwidth than that of the conventional circular patch with the identical feeding technique. Considering the common overlapped bandwidth limited by the impedance, AR and gain, the proposed annular-ring patch antenna exhibits an effective bandwidth of 38% from 1.5 to 2.2 GHz, which is wider than the corresponding bandwidth of 29.7% from 1.35 to 1.82 GHz for the conventional circular patch. Moreover, the effective bandwidth of 38% for the proposed annular-ring antenna is also much wider than those for the other annular-ring patch antennas in the literature.

Wideband Circularly-Polarized Patch Antenna

A novel wideband circularly-polarized patch antenna is presented. First, a new broadband 90deg hybrid feed network is proposed to have a bandwidth of 75% for the 10-dB return loss, good two output ports amplitude balance and a consistent 90deg (plusmn3deg) phase difference between two output ports. Then, a circular patch antenna fed by four sequential-rotation proximity-coupled L-probes orientated to have phase of 0deg, 90deg, 180deg and 270deg is presented. The four L-probes are connected to the respective ports of a feed network comprising a pair of the proposed broadband 90deg hybrid. It is found that the antenna can deliver a measured impedance bandwidth of 79.4% from 1.04 to 2.41 GHz for SWR 3 dBi. The simulated impedance bandwidth is 94% from 0.9 to 2.5 GHz for SWR 3 dBi. Good agreement is observed between simulation and measurement

Wideband circularly-polarized patch antenna

A novel wideband circularly-polarized patch antenna is presented. First, a new broadband 90deg hybrid feed network is proposed to have a bandwidth of 75% for the 10-dB return loss, good two output ports amplitude balance and a consistent 90deg (plusmn3deg) phase difference between two output ports. Then, a circular patch antenna fed by four sequential-rotation proximity-coupled L-probes orientated to have phase of 0deg, 90deg, 180deg and 270deg is presented. The four L-probes are connected to the respective ports of a feed network comprising a pair of the proposed broadband 90deg hybrid. It is found that the antenna can deliver a measured impedance bandwidth of 79.4% from 1.04 to 2.41 GHz for SWR<2, measured 2-dB and 3-dB axial-ratio bandwidths of 57% from 1.3 to 2.35 GHz and 82% from 1 to 2.4 GHz, respectively, and a measured gain bandwidth of 56.1% from 1.26 to 2.32 GHz for gain>3 dBi. The simulated impedance bandwidth is 94% from 0.9 to 2.5 GHz for SWR<2. The simulated 3-dB axial-ratio bandwidth is 63.8% from 1.25 to 2.42 GHz. The simulated gain bandwidth is 59.3% from 1.33 to 2.45 GHz for the gain>3 dBi. Good agreement is observed between simulation and measurement

Broadband Slot Antenna with Circular-Polarization Operation

In this paper, a novel wideband circularly polarized slot antenna is presented. The slot antenna with four microstrip line feeds orientated to have phases of 0deg, 90deg, 180deg and 270deg, using a feed network comprising a pair of broadband 900 hybrid was found to deliver a measured impedance bandwidth of 77.8% from 1.02 to 2.32 GHz for SWR<2, measured 2-dB and 3-dB axial-ratio bandwidths of 51.4% from 1.3 to 2.2 GHz and 88.9% from 1 to 2.6 GHz, respectively, and a measured gain bandwidth of 33% from 1.5 to 2.1 GHz for gain>3dBi. The simulated impedance bandwidth is 89.1% from 1.02 to 2.66 GHz for SWR < 2. The simulated 3-dB axial-ratio bandwidth is 81% from 1.1 to 2.6GHz. The simulated gain bandwidth is 27% from 1.6 to 2.1 GHz for the gain > 3dBi. Good agreement is observed between simulation and measurement.

Two-double Post Waveguide BPF on LTCC

In this paper, a 4.7 GHz Multilayered Substrate Integrated Waveguide (MSIW) bandpass filter based on PCB or LTCC is presented. The filter consists of one MSIW cavities in a multilayer design, with a coupling circular-post, and a slot aperture. It is found that the filter can deliver a simulated bandwidth of 100 MHz, centered at 4.67 GHz with an insertion loss of 1 dB, and a pole at 4. 48 GHz.