Yujian Li

60-GHz Substrate Integrated Waveguide Fed Cavity-Backed Aperture-Coupled Microstrip Patch Antenna Arrays

Cavity-backed patch antenna arrays with full corporate substrate integrated waveguide (SIW) feed networks are demonstrated at V-band for applications with the needs of highgain antennas. A prototype of 16 × 16 radiating elements with a waveguide transition is fabricated by applying standard printed circuit board (PCB) facilities. A gain up to 30.1 dBi with a 3-dB gain bandwidth of 16.1%, an impedance bandwidth of 15.3% for SWR <; 2, and symmetrically broadside radiation patterns with -40 dB cross-polarizations are achieved. The performance of the proposed antenna array is also systematically evaluated. The result serves as a reference for designing large antenna arrays operating at millimeter-wave frequencies.

Low-Cost High-Gain and Broadband Substrate- Integrated-Waveguide-Fed Patch Antenna Array for 60-GHz Band

A low-cost high-gain and broadband substrate integrated waveguide (SIW)-fed patch antenna array is demonstrated at the 60-GHz band. A single-layered SIW feeding network with wideband T-junctions and wideband high-gain cavity-backed patch antennas are employed to achieve high gain and wideband performance simultaneously. Although the proposed antenna array has a multilayered structure, it can be fabricated by conventional low-cost single-layered printed circuit board (PCB) technology and then realized by stacking and fixing all of single layers together. The simulated and measured impedance bandwidths of a 4 × 4 antenna array are 27.5% and 22.6% for 10 dB. The discrepancy between simulation and measurement is analyzed. A gain up to 19.6 dBi, and symmetrical unidirectional radiation patterns with low cross polarization are also achieved. With advantages of low fabrication cost and good performances, the proposed antenna array is a promising candidate for millimeter-wave wireless communication systems.

60-GHz Dual-Polarized Two-Dimensional Switch-Beam Wideband Antenna Array of Aperture-Coupled Magneto-Electric Dipoles

A dual-polarized aperture-coupled magneto-electric (ME) dipole antenna is proposed. Two separate substrate-integrated waveguides (SIWs) implemented in two printed circuit board (PCB) laminates are used to feed the antenna. The simulated -10-dB impedance bandwidth of the antenna is 21% together with an isolation of over 45 dB between the two input ports. Good radiation characteristics, including almost identical unidirectional radiation patterns in two orthogonal planes, frontto-back ratio larger than 20 dB, cross-polarization levels less than -23 dB, and a stable gain around 8 dBi over the operating band, are achieved. By employing the proposed radiating element, a 2 × 2 wideband antenna array working at the 60GHz band is designed, fabricated, and tested, which can generate two-dimensional (2-D) multiple beams with dual polarization. A measured -10 dB impedance bandwidth wider than 22% and a gain up to 12.5 dBi are obtained. Owing to the superiority of the ME dipole, the radiation pattern of the array is also stable over the operating frequencies and nearly identical in two orthogonal planes for both of the polarizations. With advantages of desirable performance, convenience of fabrication and integration, and low cost, the proposed antenna and array are attractive for millimeter-wave wireless communication systems.

A Water Dense Dielectric Patch Antenna

A novel water dense dielectric patch antenna (DDPA) fed by an L-shaped probe is proposed and investigated. In contrast to the water antennas in the literature, including the water monopole and the water dielectric resonator antenna, the operation mechanism of the proposed water DDPA is similar to the conventional metallic patch antenna. The antenna is excited in a mode like the TM10 mode of the rectangular patch antenna. An L-shaped probe, which is widely used for the conventional patch antenna, is used to excite the water DDPA. A study on the bandwidth performance of the proposed design reveals that wide bandwidth can be achieved for the antenna by choosing a thick supporting substrate between the water patch and the ground plane. A prototype is fabricated to confirm the correctness of the design. An impedance bandwidth of 8%, maximum gain of 7.3 dBi, radiation efficiency up to 70%, and symmetrically unidirectional patterns with low backlobe and low cross polarization levels are obtained. Furthermore, owing to the transparency of the water patch, the proposed water DDPA can be conveniently integrated with the solar cells to realize a dual-function design. Measurements on the prototype demonstrate that the existence of the solar cells does not significantly affect the performance of the antenna and vice versa.

A 60-GHz Wideband Circularly Polarized Aperture-Coupled Magneto-Electric Dipole Antenna Array

A novel circularly polarized (CP) aperture-coupled magneto-electric (ME) dipole antenna is proposed. The CP MEdipole antenna fed by a transverse slot etched on the broad wall of a section of shorted-end substrate integrated waveguide (SIW) is convenient to integrate into substrates. An impedance bandwidth of wider than 28.8%, a wide 3-dB axial ratio (AR) bandwidth of 25.9%, and gain of 7.7 ± 1.4 dBic over the operating band are achieved. Additionally, since the CP radiation is generated by the combination of two orthogonal ME-dipole modes, the antenna element has stable unidirectional radiation patterns that are almost identical in two principle planes throughout the operating band, which is desirable to array applications. By employing the proposed CP ME-dipole as radiating elements, an 8 x 8 high-gain wideband planar antenna array is proposed for 60-GHz millimeter-wave applications. A fabrication procedure of using conductive adhesive films to bond all print circuit board (PCB) layers together is successfully implemented to realize the array design with a three-layered geometry, which has advantages of low costs and possibility of large-scale manufacture. The measured impedance bandwidth of the fabricated prototype is 18.2% for |S11| <; -10 dB. Because of the wide AR bandwidth of the new antenna element, a wide AR bandwidth of 16.5% can be achieved by this array without the use of sequential feed. Gain up to 26.1 dBic and good radiation efficiency of around 70% are also obtained due to the use of a full-corporate SIW feed network with low insertion loss at millimeter-wave frequencies.

A Multibeam End-Fire Magnetoelectric Dipole Antenna Array for Millimeter-Wave Applications

A novel substrate integrated waveguide (SIW)-fed end-fire magnetoelectric (ME) dipole antenna is proposed. The antenna consisting of an open-ended SIW and a pair of electric dipoles has a simple structure that can be integrated into substrates conveniently. Both the open-ended SIW and the electric dipoles are effectively radiated together. Excellent performance, including a bandwidth of 44%, symmetrical radiation patterns that are almost identical in two orthogonal planes, low backward radiation, low cross polarizations, stable gain of around 5 dBi, and wide beamwidth of around 110°, are also obtained. An 8×8 SIW Butler matrix is then designed. Modifications to the geometry of the matrix provide more spacing to locate SIW phase shifters and phase compensation structures with wide bandwidth. By employing the proposed end-fire ME-dipole antenna array and the 8×8 Butler matrix, an eight-beam antenna array is realized. The fabricated prototype demonstrates that wide bandwidth, stable radiation patterns with cross polarizations of less than -28 dB and gain varying from 9 to 12 dBi can be obtained. The proposed multibeam end-fire ME-dipole antenna array would be an attractive candidate for millimeter-wave wireless applications due to its good performance, ease of integration, and low fabrication cost.

A Broadband V-Band Rectangular Waveguide to Substrate Integrated Waveguide Transition

A broadband air-filled rectangular waveguide to substrate integrated waveguide (SIW) transition is proposed at V-band. By introducing an aperture coupled patch antenna structure into the design, a bandwidth wider than 35% for |S11| <; -10 dB is achieved. A back-to-back prototype fabricated by the low-cost printed circuit board (PCB) technology shows that the insertion loss of a single transition is less than 0.58 dB within the bandwidth. With good performance and compact volume, the proposed transition is attractive for millimeter-wave circuit designs and measurements.

A 60-GHz Dense Dielectric Patch Antenna Array

The dense dielectric (DD) patch antenna is investigated at the 60-GHz band. By employing the printed circuit board (PCB) technology, a 4 4 aperture-coupled DD patch antenna array is designed, fabricated and studied. An impedance bandwidth of 23.7% from 51.3 to 65.1 GHz for |S11| <; -10 dB, a gain up to 16.5 dBi with a 3-dB gain bandwidth of 32.5%, and symmetrical broadside radiation patterns with -15 dB cross-polarization are achieved.

A Linearly Polarized Magnetoelectric Dipole With Wide H-Plane Beamwidth

A linearly polarized magnetoelectric (ME) dipole with wide beamwidth in the H-plane is proposed and studied. A fabricated prototype shows that stable wide beamwidth of 120 ° in the H-plane is achieved across the 41% impedance bandwidth for SWR ≤ 2 with good radiation performances including a stable gain around 6.3 dBi, symmetrically unidirectional radiation patterns, low cross polarization, and low back radiation. Design guidelines and three design samples are given, which demonstrate that the beamwidth in the H-plane can be varied over a range larger than 30 ° from 90 ° to 120 ° and the fluctuation of the beamwidth is less than 10 ° throughout the whole operating band. Besides, it shows that the variation in the H-plane does not degrade the other performances of the antenna. With all of these advantages, the proposed antenna is a desirable candidate for base stations of mobile communications which require antennas of different beamwidths for different environments.

Wideband Perforated Dense Dielectric Patch Antenna Array for Millimeter-Wave Applications

A wideband perforated dense dielectric (DD) patch antenna array fed by a single-layered substrate integrated waveguide (SIW) feed network is investigated for millimeter-wave applications. The proposed antenna array offers advantages of wide bandwidth and good radiation performance simultaneously and can be fabricated conveniently by the standard printed circuit board (PCB) technology. A 4 × 4 prototype operated at the 60-GHz band is designed, fabricated, and measured to demonstrate the design. An impedance bandwidth of 23% for SWR <; 2, a gain up to 17.5 dBi with a 3-dB gain bandwidth of 24%, symmetrical unidirectional radiation patterns with cross polarization levels of less than -20 dB are achieved.