Yang Caitian

A Novel Printed Fractal Log-Periodic Dipole Antenna

This paper presents the research on a novel miniaturized printed log-periodic antenna with fractal tree structure for operation in a broadband of 0.4 GHz-2GHz. The antenna is designed and simulated with the application of CST MICROWAVE STUDIO®software based on the Finite Integral Method. The simulation results show that the antenna achieves the necessary lateral size reduction to 61% of the normal log-periodic antenna, while keeping its radiation characteristics nearly constant.

A triple-frequency circularly polarized microstrip antenna

A triple-layer patch circularly polarized microstrip antenna is proposed for triple-frequency operation. It is shown that the antenna resonates at three different frequencies of 1.207GHz, 1.268GHz and 1.561GHz with adequate values of return loss and gain. The antenna is designed and simulated with the application of CST software based on the finite integral method. The simulation results and analyses are presented.

A Triple-Frequency Circularly Polarized Microstrip Patch Antenna

In this paper, a circularly polarized microstrip patch antenna is proposed for triple-frequency operation. To achieve triple-frequency operation, the proposed antenna has three layers. The proposed antenna is designed and experimentally analyzed at three different frequencies. From the measured results, the resonator frequencies of this antenna are 1.207GHz, 1.268GHz and 1.561GHz, and the measured impedance bandwidths are 22MHz, 10MHz, and 40MHz for VSWR<2. The measured gains are 4.15dBi, 3.75dBi, and 3.05dBi, respectively, and the lowest gain at low-angle (at an elevation of 10 degrees) is -0.5dBi. The measured results and analyses are presented

Novel ultra-wide band omni-directional dipole antenna

Based on the conventional ultra-wide band (UWB) circular disk monopole antenna, a novel omni-directional dipole antenna is investigated both numerically and experimentally in this paper. The results demonstrate that the antenna can work well in the 1.75GHz~40GHz frequency range. Compared with the conventional antenna, the proposed antenna has better omni-direction characteristics in H-plane radiation pattern and the main direction of the E-plane radiation pattern keeps stable. The proposed antenna provides the valuable reference for the future ultra-wide band omni-directional antenna design and shows great value in the fields of communication and radar system.

Planar composite triangle monopole UWB antenna

A novel planar composite triangle monopole ultrawideband antenna fed by microstrip is proposed in this paper. Radiating element of the antenna is a combination of three similar triangles from small to large, and the width of the microstrip change gradient. Simulation results from CST software demonstrate that the antenna has stable input impedance and stable patterns in the 3.1–10.6GHz, with H plane omni-directional radiation characteristic, which is suitable for short-range wireless ultra-wideband communications.

Research on quasi-optics and feed antenna for Millimeter wave imaging system

The quasi-optics sub-system of Millimeter-wave focal plane arrays imaging system includes the design of system parameters, multi-beam design of focusing element and design of feed antenna. Design of focusing element decides the spatial resolution and the maximum field of view of the system. The design and arrangement of the feed antenna related to the overflow efficiency and the spatial sampling rate of the system. In this paper, fundamental mode Gaussian beam method is taken to design quasi-optics, and focusing lens antenna is designed with the principle of optical path difference of feed sources on optical axis. In this paper also proposed a new kind of dielectric rod antenna with new structure as the feed source to the lens. The simulation and measurement show that the multi-beam lens antenna has a better wide-angle scanning feather. The feed antenna has broader wave band, lower side lobe, lower mutual coupling, lower cross polarization, and the gain of it can be changed by changing its length but not the section area. It is easier to form a close feed array which can realize an effective exposure to the lens or the reflector antenna with less overflow loss.

A novel semi-circle fractal multi-band antenna

This paper proposes a novel multi-band semi-circle fractal antenna which develops from the multiple ring antenna. The antenna consists of nesting semi-circles with different radii. Simulated on the commercial software CST MICROWAVE STUDIOreg, the multi-band characteristic of the novel antenna can be controlled by modulating the radii of the nesting semi-circles and the nesting number. Summarized from the impact of these parameters, antenna with three passbands (900 MHz, 1.8 GHz, and 2.4 GHz) has been designed. In order to remove the infinite conductive ground, the antenna patch is placed on FR4 board and fed to get the printed antenna. The simulation results indicate that the antennas also have three pass bands with the same central frequencies with wide bandwidths. The antenna is manufactured and measured, the experiment results fit well with simulation. Thus, the multi-band semi-circle fractal antenna is a novel antenna with controllable frequency bands and promising application.

Novel ultrawide-band omnidirectional circular disk monopole antenna

The ultrawide-band antenna is one of the hot research areas. Based on the conventional ultrawide-band circular disk monopole antenna, a novel miniaturized ultrawide-band monopole antenna is presented in this paper. The simulation results demonstrate that the antenna can work well in the 2.3GHz∼24GHz frequency range. Compared with the conventional antenna, the novel antenna has better omnidirection in H-plane radiation pattern. It is proposed to be used in mobile communication and satellite communication with good prospects.

A printed trapezoid dipole broadband antenna

The feed part which uses gradually changing structure usually has wider impedance bandwidth. A kind of trapezoid dipole antenna that is similar to the parallel dual-feed is analyzed in the essay. Adopting the software of CST Microwave to simulate how the structure parameter of antenna influences impedance character, a type of dipole antenna working within 1.85∼3.75GHz is designed. The simulation results and experiments indicate that the antenna possesses wide impedance bandwidth. Meanwhile, the pattern is approximately omni-directional within the frequency band. So the antenna can be used in many fields, such as PCS, WLAN, WiMAX, and so on.

The simulation research of an S-band low-sidelobe antenna

An S-band low-sidelobe antenna is designed and proposed which fosters the character of small size and simple structure with wide bandwidth in this paper. The antenna to be discussed takes the advantage of short -focus paraboloidal reflector with round chip and is fed with half-wave dipole. Adjusting the amplitude-phase distribution of aperture field of the antenna, the demand for low-sidelobe and high gain is satisfied through a wide frequency range. The antenna contributes to the portable device for its short vertical length. Simulated on CST MICROWAVE Studioreg, E-plane and H-plane directional diagram results illustrate that the antenna satisfies following character through a wide frequency range: the maximum sidelobe les-20 dB, the gain ges 20 dBi, the half-power beam width (HPBW) les 20deg. Besides, within the frequency range of the central frequency plusmn 50 MHz the antenna shows ultra-low sidelobe and satisfies its maximum side lobe les-30 dB. At the same time, the collision between low-sidelobe and beam width is solved successfully.