Wanchen Yang

Novel Polarization Rotation Technique Based on an Artificial Magnetic Conductor and Its Application in a Low-Profile Circular Polarization Antenna

A novel polarization rotation technique based on an artificial magnetic conductor (AMC) structure is proposed. A new polarization rotating reflective surface (PRRS) is designed using a newly proposed AMC as the unit cell. The height of the so-constructed PRRS is only 0.04 λ0. Our theoretical analysis shows that the polarization rotation property of the new PRRS is due to an impedance imbalance which can be analyzed using an equivalent circuit model. In addition, two polarization rotation bands and a large polarization rotation bandwidth of 29.1% can be achieved by using the new PRRS. Moreover, the new PRRS is applied for the first time to design a low-profile dipole antenna for the generation of circular polarization radiation. Three polarization states are readily achieved. Both simulation and measurement results demonstrate good right-handed circular polarization with a broad axial ratio bandwidth and a large axial ratio beamwidth in both the xoz and yoz planes.

A Polarization-Reconfigurable Dipole Antenna Using Polarization Rotation AMC Structure

A novel polarization-reconfigurable mechanism based on a polarization-rotation artificial magnetic conductor (PRAMC) structure is proposed. A new polarizationreconfigurable antenna is designed by combining a PRAMC-based multipolarized dipole antenna with a RFIC switch-based network, in which three polarization states of right-handed, left-handed circular polarization (RHCP, LHCP) and +45° linear polarization (LP) can be realized by controlling the dc bias of the switches accordingly. The multipolarization antenna is well designed for offering three polarization states. A large 3-dB axial ratio (AR) bandwidth of 15.5%, a wide 3-dB AR beamwidth for CP states and a large cross-polarization isolation of more than 50 dB for LP state together with a broad impedance bandwidth of 20.5% are obtained. A switch network is used to generate three feeding modes, and the performance of the RF-integrated circuit (RFIC) switches is experimentally verified. A prototype of the proposed polarization-reconfigurable antenna is fabricated and tested. Good agreements between the measured and simulated results are observed, which indicates good performances of the proposed antenna.

Miniaturized Patch Antenna With Enhanced Bandwidth Based on Signal-Interference Feed

In this letter, a miniaturized microstrip patch antenna with enhanced bandwidth is presented. Based on the transversal signal-interference concept, the dual feedline structure is employed to reduce the nonradiating side of the antenna element. In order to extend the impedance bandwidth, an additional T-shaped stub resonator is introduced. Compared to a typical rectangular patch antenna, 32% size reduction and 17.0% impedance bandwidth (S11<;-10 dB) enhancement are achieved, respectively. Good agreement between simulation and measurement can be observed.

60-GHz LTCC Differential-Fed Patch Antenna Array With High Gain by Using Soft-Surface Structures

This paper presents a 60-GHz 4 × 4 differential -fed patch antenna array using low-temperature cofired ceramic (LTCC) process. Wideband patch with L-shaped feeding scheme is adopted as antenna element, while differential substrate integrated waveguide feeding network with low insertion loss is applied for the integration of antenna array. The differentialfed structure improves the symmetry of radiation patterns and reduces the cross-polarization level significantly. To further suppress the surface wave and improve the gain of the antenna array, one kind of soft surface structure is proposed. The equivalent circuit model of the soft surface is developed for calculating its dispersion diagram and analyzing stopband characteristics. The simulated results indicate that the antenna gain enhancement can be up to 2 dB because of the proposed soft surface. For demonstration, one prototype using LTCC process is fabricated and measured. The measured 10-dB impedance bandwidth of the antenna array is 11.7%. The measured antenna peak gain of 18.62 dBi at 61.5 GHz and symmetrical radiation patterns with a low cross polarization of -25 dB across the whole operating frequency are achieved.

High-gain low-cross-polarization 60-GHz LTCC patch antenna array with differential-fed and soft-surface structures

A 2×2 60-GHz differential-fed patch antenna array was developed using low-temperature co-fired ceramic (LTCC) multilayer technology with high gain and low cross-polarization level. The antenna elements were constructed by radiation patches and folded L-shaped feeds. A novel soft-surface structure was designed to suppress the surface wave and enhance antenna gain. Substrate-integrated waveguide (SIW) and differential-fed structures were applied to reduce the loss of feeding network and the cross polarization level. The proposed antenna array achieves flat gain curve over the range of 55-65 GHz with a peak gain of 13.6 dBi at 62.1 GHz. The simulated cross polarization level was lower than -35 dB in both E-plane and H-plane.

94-GHz Compact 2-D Multibeam LTCC Antenna Based on Multifolded SIW Beam-Forming Network

This communication presents a compact 94-GHz 2-D multibeam antenna using the low-temperature co-fired ceramic (LTCC) technology. A good 2-D substrate integrated waveguide (SIW) beam-forming network (BFN) for eight beams is proposed, where four-phase shifters are properly introduced to increase the flexibility of the beams. Benefiting from multilayer LTCC, the BFN is compactly implemented in a completely symmetrical structure by using two multifolded SIW Butler matrixes with 50% reduction of the longitudinal size, and four couplers placed on different layers with interlaced signal routes to avoid overlaps or crossovers. Combined with a

High-gain 60-GHz patch antenna array using GaN MMIC technology

2 \times 4

High-efficiency microstrip patch antennas using non-periodic artificial magnetic conductor structure

SIW slot antenna array, the multibeam antenna can realize eight symmetric scanning beams on 2-D with stable gains for a wide coverage. For demonstration, the two single-port antennas with different pitch-angle beams are fabricated and measured, and good agreements with the expectations are observed. The differences of the beam orientations are less than 5°, while the measured peak gains of the beams are about 8.5 dBi.

Antenna pair with self-interference cancellation for full duplex communication

In this paper, a high-gain 2×2 antenna array at 60 GHz using GaN MMIC process technology is presented. For gain enhancement, a modified patch antenna element with two parasitic strips on each non-radiation edge and a parasitic patch on one of the radiation edges is proposed. This antenna element achieves a gain of 3.42 dBi at 60 GHz, about 2 dBi higher than a conventional patch antenna element using the same process technology. The 2×2 antenna array consisting of four modified patch antenna element exhibits a 10-dB impedance bandwidth of 10.1% and a peak gain of 5.7 dBi at 60 GHz.

Multi-functional antennas using polarization-rotation artificial magnetic conductor structures

A novel artificial ground composed by several non-periodic rectangle artificial magnetic conductor (RAMC) structures is firstly proposed, and employed as the ground plane of a probe-fed patch antenna. Based on the design strategy of parasitic patches, the dimensions and arrangements of these RAMC cells in the artificial ground as well as the size of the ground plane are investigated and discussed. As results, two RAMC-based antennas with high efficiency are proposed, which respectively can achieve very high efficiency of over 90% and stable efficiency of over 80% within the operating frequency band. For demonstration, two proposed antennas are fabricated and measured. Good agreement can be observed between the simulated and measured results.