Song Lizhong

Design and measurement of a kind of dual polarized Vivaldi antenna

This paper designed and fabricated a dual polarized ultra wide band (UWB) Vivaldi antenna in order to meet the requirement of the practical work. The discussed working frequency range of the designed antenna is 3.1∼10.6GHz, the designed dual polarized Vivaldi antenna is composed of two single polarized Vivaldi antennas which are orthogonally laid. For each single polarized Vivaldi antenna, a linear tapered microstrip feeding structure is designed to realize the impedance matching. These two feeding microstrip lines are separated to realize independent feeding of each polarized port. The structure and parameters of the dual polarized Vivaldi antenna is designed and simulated. The fabricated dual polarized Vivaldi antenna is measured in the anechoic chamber. The isolation degree is about 20dB and the gain o f each polarization port is larger than 1.37dBi. Some measured patterns and gain curves are given. Yet the performances of two ports are not symmetric and some characteristic parameters are not ideal compared with the simulation results which should be further improved through improving the fabrication level. The design and experimental results in this paper can provide a technical reference for the fabrication of other dual polarized UWB antennas.

Simulation and analysis of a hemispherical conformal sinuous antenna with four arms

In this paper, a hemispherical conformal sinuous antenna with four arms is discussed. The radiation performances of a specific hemispherical conformal sinuous antenna model are simulated and analyzed. The structure and parameters of the discussed antenna are introduced and the simuation results inidcate that the discussed antenna has still the ulra wide band (UWB) charatersitics of impedance and wide beam within the working frequency range from 3GHz to 18GHz. The input voltage standing wave ratio (VSWR) is ameliorated by loading a resistor with 50Ω at the end of the two arm. At many frequency ponits within the working frequency range, the discussed antenna has approximately orthogonal dual linear polarization characteristics. It should be also noted that the patterns fluctuate when the frequency increases and the coupling is relative strong between two polarization ports. The simulated results can become a reference for the design and fabrication of this kind of antenna in practical applications.

Design and simulation of a waveguide slot antenna

Due to low efficiency in waveguide slot antenna design, this paper proposes a method which combines numerical calculation with numerical simulation. We apply slot self-admittance extracted from the software to the active admittance formula. Then the normalized slot active admittance is obtained. This method completely considers the mutual coupling between slots. The normalized slot active admittance is accurate and can be directly used in antenna design. The simulated results of waveguide slot antenna prove that this method has high efficiency and can be used in waveguide slot antenna design.

Scheme of adaptive polarization filtering based on Kalman model

Abstract A new kind of adaptive polarization filtering algorithm in order to suppress the angle cheating interference for the active guidance radar is presented. The polarization characteristic of the interference is dynamically tracked by using Kalman estimator under variable environments with time. The polarization filter parameters are designed according to the polarization characteristic of the interference, and the polarization filtering is finished in the target cell. The system scheme of adaptive polarization filter is studied and the tracking performance of polarization filter and improvement of angle measurement precision are simulated. The research results demonstrate this technology can effectively suppress the angle cheating interference in guidance radar and is feasible in engineering.

Design of a new dual-polarization antenna on missile

Dual-polarization antenna on missile is useful in some applications such as target detection and counter-countermeasure. But it is difficult to design and fabricate because of the limited space in the missile. This paper discusses the design of a new X band dual-polarization Cassegrain antenna for guidance radar on missile, including the calculation of the parameters of the ortho-mode transducer. The ortho-mode transducer is adopted, which enables the antenna to transmit and receive vertical and horizontal polarization signal. The measurement of the new antenna shows that its polarization isolation is high enough to meet the need and the other performances are almost the same as those of the original simple-polarization antenna.

Performance simulation of a kind of conformal sinuous antenna with four arms

This paper discussed a kind of conformal sinuous antenna which is mounted on the surface of the circular truncated cone. The radiation performances of the proposed antenna are simulated and analyzed. Firstly, the planar sinuous antenna with four arms is constructed, then it is projected on the surface of a circular truncated cone and the conformal sinuous antenna with four arms is formed. The bottom diameter and the height of the cone are 60 millimeters and 30 millimeters, respectively. The simulation results reveal that the simulated antenna has ultra wide band (UWB) characteristics for the frequency range from 2GHz to 8GHz. The average voltage standing wave ratio (VSWR) is 3 when the characteristic impedance of the transmission line at the terminal is 180Ω. Within the working frequency range, the beam is wide, but the main lobe direction changes notably when the frequency changes. For several working frequency points, the simulated antenna has approximately orthogonal dual polarization characteristics. Yet the coupling between two polarization ports is strong. The proposed antenna has narrower bandwidth compared to planar sinuous antenna. The proposed conformal sinuous antenna has still the UWB and approximate dual polarization characteristics for certain frequency range, moreover, it is a kind of conformal antenna, which can be used in some special working cases.

Angle glint suppression for millimeter-wave radar based on polarization filtering

For the millimeter wave radar, angle glint of extended targets is the main angle error. A new kind of dual polarization wide band millimeter wave radar is proposed and a glint suppression technology based on polarization filtering is studied in this paper. Firstly the echo-signal is processed into one dimension range profile based on high range resolution of millimeter wave radar and the effective strong scattering centers are detected, secondly the polarization filtering is used to the signals in the range cell where the scattering centers exist in order to suppress clutter and increase the angle measurement precision of single scattering center, finally the angle of each scattering center is measured by amplitude sum/difference and the target average angle is obtained by weighting all the scattering centers, which can realize the correct track on the target. Theoretical analysis and simulation results indicate that the technology can obviously increase the angle measurement precision of the whole target.

Design and simulation of a kind of monopole antenna fed by SICL

Substrate Integrated Coaxial Line (SICL) is a kind of planar coaxial transmission line, which has completely shielded and non-dispersive structure. SICL has the characteristics including wide band, low loss and miniaturization. This paper researched a monopole antenna fed by SICL. A triangle monopole was adopted as the radiator with the frequency range from 1.35GHz to 1.65GHz. The SICL feeding structure was designed and simulated through the full wave electromagnetic simulation technique. The simulated voltage standing wave ratio (VSWR) of designed monopole antenna was less than 2 within the operating frequency range of 1.32GHz to 1.66GHz, and the relative frequency band was about 20%. The designed antenna achieved the anticipated gains which were higher the 2dBi for the operational frequency range. The radiator size of monopole antenna was about 33mm X 15mm × 2mm, and antenna miniaturization was achieved. The discussed monopole antenna fed by SICL showed the nearly omnidirectional radiation pattern and high radiation efficiency. Moreover, it had a simple structure, which was favorable for the practical application.

Novel conformal Vivaldi antenna fed by CPW

In order to realize the function of angle measurement for passive radar seeker, a novel Vivaldi antenna fed by CPW is designed. The novel structure can be more suitable for conformal because of its single side property. Elliptical slot is introduced to improve the distribution of surface current. Side fed has achieved miniaturization. The proposed antenna including the feeding line and transition measures 229×218×1mm3 and has a peak gain >4.2dBi over the 0.8-4 GHz frequency range.

Research on a kind of anti-podal Vivaldi antenna

This paper researched a kind of antipodal Vivaldi antenna for passive guidance radar application on the missile. In order to achieve better characteristics of end-fire, a rectangular slot was used to change the antenna surface current distribution on the basis of the original antenna. To solve the problem of low gain for the conventional antipodal Vivaldi antenna, an ellipse parasitic patch was introduced at the end of radiation zone of the antipodal Vivaldi antenna. Simulation results showed that the average gain of the antenna is increased by 2.5dBi. Finally, this paper discussed the performance changes of the antipodal Vivaldi antenna unit when it is conformal with the surface of a cylinder. The analysis and simulation result were provided and can be as a technical reference for the practical engineering application.