Chaoyuan Ding

A PLANAR U TYPE MONOPOLE ANTENNA FOR UWB APPLICATIONS

An ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed. It has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm). It provides an wide impedance bandwidth ranging from 3.08 GHz to about 12.75 GHz adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and feed and ground plane dimensions. Parametric study is presented. Details of the proposed ultra-wideband design are described. Simulation results are presented and discussed in this paper.

A Compact Ultra-Wideband Microstrip Antenna with Multiple Notches

In this paper, a new compact circular monopole ultra- wideband antenna with multiple narrow bands notched is proposed, which is implemented by using the existing techniques, such as loading a L-type band-stop filter, inserting a split ring resonator (SRR), and the method we proposed that connecting L branches on the radiation disk. Four sharp notches at 2.4GHz, 3.5 GHz, 5.5 GHz, and 7.6 GHz are achieved separately. The measured VSWR shows a good agreement with the simulation results. The radiation patterns are obtained from Ansoft HFSS simulations and verified by CST Microwave Studio. The results prove that this kind of antenna can be applied in the UWB communication systems to avoid interference with other wireless systems, such as the 2.4GHz WLAN, 3.5 GHz WiMax, and 5.8 GHz WLAN etc. The parameters determining the antennas band notched characteristic are discussed.

A novel archimedean spiral antenna with uniplanar EBG substrate

A gap-loading Archimedean spiral antenna with uniplanar EBG is presented in this paper. Utilization of the gap-loading technique offers an antenna lowest operation frequency reduction of more than 0.5 GHz. The uniplanar EBG is of benefit to reduce the height about 60%, including the thickness of EBG structure, compare to the traditional lambda/4 cavity backed implementation of Archimedean spiral antenna. Further investigations indicate that the radiation patterns and 3 dB angular width are both stable in the range of 2 GHz-5 GHz.

A novel periodic defected ground structure for microstrip line with improved performances

A novel one-dimensional (1-D) defected ground structure (DGS) for the microstrip line is proposed. Different from the square-shaped DGS (SSDGS), the improved DGS (IDGS), which hold four stubs to disturb the fields in the square defected pattern, improved the effectuve capacitance and inductance at high frequencies, and provide a very wide bandgap characteristic with only one or more unit lattices. The performance of the unit DGS is investigated. A uniform periodic SSDGS and IDGS are designed and study. The research work show that the IDGS exhibit more excellent performances by generating stopband at high frequency bands.

A new band-notched printed monopole antenna for UWB applications

An ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) with band-notch characteristic is proposed. Printed on a 0.8 mm thick FR4 substrate with relative permittivity of 4.4, it has low profile and very compact size (14.48 mm times 28.74 mm), only around 0.14 lambda times 0.28 lambda in electrical length (lambda is the wavelength of lower frequency 2.95 GHz). It provides an wide impedance bandwidth ranging from 2.95 GHz to about 12.65 GHz (124.4%), and presents a notched band from 5.13 to 5.9 GHz for VSWR- 3, which covers the wireless local area network (WLAN) band. The time-domain behaviors are discussed and the group delay is given. The proposed antenna has a compact size, ultra wide bandwidth, good radiation characteristics, and good time-domain behaviors to satisfy the requirements of the current and future wireless communications systems. Details of the proposed ultra-wideband design are described and parametric study is presented.

Wideband planar open-sleeve dipole on magnetic dielectric material based EBG substrate

Open-sleeve dipoles are widely used antennas because they have several parameters that can be adjust to achieve wide range of operating bandwidth. In this paper, an end-loaded planar open-sleeve dipole (ELPOSD) with a magnetic dielectric material based planar EBG substrate is investigated. With S11 ≪ −10 dB, the ELPOSD has a bandwidth of 5.15–10 GHz and the broadband gains precede 6.4 dBi. Including the thickness of the EBG substrate, the antenna height is reduced 60% at the central frequency, compare to the traditional quarter wavelength cavity backed ELPOSD antenna. Especially, the lower frequency reaches 5.15 GHz, which is reduced 1.1 GHz.

Miniature filters based on Metamaterials with transmission zeros and wide upper-stopband performance

In this paper we have proposed a Metamaterial based Composite Right-Left Handed transmission line new structure with microstrip gap capacitor and stub inductors shorted to the ground plane by via to achieved miniature filters with two transmission zeros and wide upper-stopband performance. The proposed designs take advantage of different aspects of metamaterial behaviour to achieve miniature and wide upper-stopband characteristics. The designed filter has a compact structure with overall dimensions of 1/7 λg by 1/10 λg. The designed filter type 2 has two transmission zeros at 2.66 GHz and 3.25 GHz, a 3 dB bandwidth of 29.8% at 1.51 GHz, insertion loss of −3 dB, attenuation greater that 55 dB in the lower stopband and the attenuation at higher stopband is greater that 17 dB extend to a frequency higher that 8 GHz.

A back-to-back planar folded dipole on EBG substrate

A planar antenna composing two back-to-back folded dipoles printed on a dielectric substrate is presented and the performances are investigated when it is mounted on a mushroom-like EBG substrate. A wide impedance bandwidth is achieved of 4.95–6.95 GHz for the constructed prototype, about 33.6% of the central frequency. Within the operation band, stable gain and radiation patterns are obtained, and the back radiation is less than −27 dB. Whether in E plane or in H plane, the cross polarization is small enough to be negligible.

A miniature broadband semi-circular fed patch antenna on a small-size ground plane

A double layer patch antenna for wideband and small size is proposed. By introducing a long U-shaped notch and semi-circular feeding, a wide bandwidth of 62% for the return loss (S11) < -10 have been achieved. Besides, the ground plane size of the proposed antenna is relatively small compared with other patch antenna.

A Novel Wideband Electrically Small Monopole

This letter proposed a broadband wire antenna with vertical polarization and omni-directional features, operating from 225 MHz to 700 MHz. By introducing the gap and lump elements loading, broad impedance bandwidth is achieved, and the electrically length of this novel antenna is only 0.13 λ.