Wanchu Hong

A Novel Dual Circularly Polarized Microstrip Antenna

In this paper, we propose a novel design of dual circularly polarized microstrip antenna of the cogwheel-like annular ring structure. The microstrip sector stubs are added periodically in the outer and inner edges of the microstrip annular ring and an additional microstrip line as a diameter is also placed across the inner circle to enhance performance of the axial ratio. When operated in TM11 mode, this cogwheel-like microstrip annular ring antenna has a relatively wider bandwidth and a relatively smaller size than those of the traditional microstrip annular ring antenna. The three-wire transmission line and branch-line hybrid is employed as the feeding network to excite the righted-handed or left-handed direction of circular polarization

Balanced BPF design using the substrate integrated waveguide

In this paper, we present a novel design of a balanced bandpass filter using the substrate integrated waveguide cavity. Two square-shaped substrate integrated waveguide cavities are side-by-side with removing the vias on the common sidewall to form the BPF. Pared microstrip lines are used to construct the balanced ports of the proposed circuit. Slots are utilized to perturb the degenerated modes of TE102 and TE201 modes. Common-mode signals are managed to be suppressed for a better performance.

Space-Wave Leakage of Strip Lines on Circular Substrate

The space-wave leakage of strip lines on circular substrate is analyzed for the first time. The circular curved single-conductor strip structure has the broader bandwidth of the space-wave radiation than planar structure and is less affected by the surface wave leakage. This structure is suitable for the leaky-wave antennas for wireless broad-band communication applications

Design of magnetic antenna with dual circular polarizations

This paper proposes a novel magnetic antenna with dual circular polarizations. Two circular loop antennas are arranged in spatially mutual orthogonality. The differential branch-line coupler, which can generate a set of four quadrature phases of 0, 90, 180, and 270 degrees with equal amplitude, is designed and used to excite the magnetic loop antenna. Right-handed or left-handed circular polarization (RHCP or LHCP) is determined by the sign of relative phase difference. The numerical results of the scattering parameters and the radiation patterns are presented.

Dual-Band BPF Composed of Doubly-Coupled λ/2 and λ/4 SIRs for WLAN Applications

This paper presents a dual-band bandpass filter composed of lambda/2 and lambda/4 stepped impedance resonators (SIRs) for the WLAN applications. The filter covers both the operating frequencies of 2.45 and 5.2 GHz. The doubly parallel-coupling mechanism is used in the filter design to provide alternative routes for signals of distinct frequencies. The tapped-line I/O feed is adopted in this circuit to create the attenuation poles for improving the signal selectivity and stopband rejection levels. Experiments are conducted to verify the circuit performance.

Design of a novel planar Bulter matrix beamformer with two-axis beam-switching capability

By employing one microstrip patch array and one single-conductor microstrip leaky-wave array on the same substrate, a novel planar Bulter matrix beam-forming array that can switch beams in two orthogonal axes is proposed in this paper. Numerical simulation and experimental results are shown to demonstrate its two-axis beam-switching capability. With its printed circuit form, it is very suitable for integration into modern wireless communication systems with smart antenna techniques.

A novel dual-band grid array antenna for LTE small cell base station applications

In this paper, we propose a simplified grid array antenna design using the open strip loops integrated with the grid slots in the ground plane. The insertion of Teflon layer make the currents concentrate on some strip lines. The shorting walls are used to set the resonant frequency band and to improve the impedance matching. The design can effectively miniaturize the antenna size and wide bandwidth for dual band operation. The simulated and measured results demonstrate this proposed design well.

A small antenna for DVB-H application

In this paper, we propose a kind of planar monopole antenna for DVB-H system. This antenna only uses metal sheets with simple geometrical structure to lower the cost and to be easily manufactured. With a small size of 90x50 mm2, this antenna is very suitable to be imbedded into any handset-type multimedia products.