Fu Demin

Microstrip fractal patch antenna for multi-band communication

A novel square microstrip fractal patch antenna in a Sierpinski carpet is proposed for three-band operation. Theoretical analysis and measurement of the antenna are carried out. This antenna is an attractive candidate for wireless, satellite and mobile communication applications.

Analysis and simulation of system phase errors in planar near-field measurements on ultra-low sidelobe antennas

System phase errors are one of the main error sources to influence the precision of planar near-field antenna measurements, especially for planar near-field measurements on ultra-low sidelobe antennas. In this paper, the effect of system phase errors on the results of planar near-field measurements on ultra-low sidelobe antennas is studied by means of theoretical analysis and computer simulation. The analytical expression of the error spectrum in the sidelobe region due to system phase errors is derived and some basic laws and useful results are obtained.

Application of the Window Function in Bistatic Planar Near-Field Scattering Measurements

The cosine window function is introduced and applied in the planar near-field scattering measurements. Based on the basic principle of which, the bistatic planar near-field scattering measurement technique is computer simulated with the infinite long ideal conductor cylinder as the target under test. The calculation results show that in bistatic planar near-field scattering measurements, the finite scanning plane truncation errors of the far-field RCS of the target under test obtained by near-field to far-field transformation can be reduced greatly by the weighting process of the measured scattering near-field with the cosine window function, which proves the validity and applicability of the near-field data processing method by means of the cosine window function in the bistatic planar near-field scattering measurements.

Application of the Window Function in the Plane Wave Synthesis Technique

The cosine window function is introduced and applied in the plane wave synthesis technique. With the infinite long current filament as the scanning probe, the plane wave synthesis technique is computer simulated. The calculation results show that in the plane wave synthesis technique, the uniform degree of the amplitude and phase of the quasi-plane wave synthesized in the body under test zone can be improved greatly by weighting process of the current distribution of the array elements with the cosine window function, which proves the validity and applicability of the weighting method by means of the cosine window function in the plane wave synthesis technique.

A near-field diagnostic technique based on equivalent magnetic currents

A new technique is presented for determining the amplitude and phase distribution over the aperture of the antenna under test from planar near-field measurements. The main computational formulae are provided and proven to be accurate and effective by use of the detailed numerical simulation compared with the related literature and an experiment.

A novel near-field measurement method for predicting far-field monostatic RCS of targets

A novel near-field measurement method for predicting far-field monostatic RCS of targets is studied. With the two-dimensional problem as an example, the theory and algorithm of near-field to far-field transformation for this measurement method are derived. With the two-dimensional perfect conductor plate as the target under test, the computer simulation of this measurement method is performed. The calculation results show that the far-field monostatic RCS obtained by near-field to far-field transformation agrees with the far-field monostatic RCS calculated theoretically very well, which proves the correctness and validity of this measurement method.

Plane wave synthesis based on the Least Square Method

A novel method of plane wave synthesis is presented with the application of the least square method in the plane wave synthesis technique. With the rectangular planar array made up of the half-wavelength dipole elements as the theoretical model of plane wave synthesis, the novel method is used to seek optimum amplitude and phase distribution of array element so as to make the uniform degree of the amplitude and phase of quasi-plane wave synthesized to be the best. The calculation results show that the method presented in this paper requires smaller probe array than the traditional methods in order to ensure the quality of quasi-plane wave synthesized, which proves the correctness and validity of the novel method.

Study of self-transmitting and self-receiving monostatic planar near-field scattering measurements

The technique of self-transmitting and self-receiving (STSR) monostatic planar near-field scattering measurements is studied and computer simulated. Calculation results indicate the relative value of monostatic RCS obtained by means of self-transmitting and self-receiving monostatic planar near-field scattering measurements has good engineering precision in an angle range near the outward normal direction of the scanning plane. Finally, several problems that need to be further studied are pointed out.

Application of the Least Square Method in the Plane Wave Synthesis Technique

A novel method of plane wave synthesis is presented with the application of the least square method in the plane wave synthesis technique. With the linear array made up of the infinitely long current filament as the theoretical model of plane wave synthesis, the novel method is used to seek optimum amplitude and phase distribution of array element so as to make the uniform degree of the amplitude and phase of quasi-plane wave synthesized to be the best. The calculation results show that in the case that the size of the region under test remains unvaried, the method presented in this paper requires smaller probe array than the traditional methods in order to ensure the quality of quasi-plane wave synthesized, which proves the correctness and validity of the novel method.

Optimization and Application of the Yagi-Uda Antenna for Meteor Burst Communication

A wide-band Yagi-Uda antenna with an x-shape driven dipole for the Meteor Burst Communication (MBC) at the VHF is presented in this paper. The parameter design and multi-objective optimization process of the proposed antenna are given. And effects of the installed height on the performance of the antenna are also studied in detail. The simulated and measured impedance bandwidth of VSWR<1. 4 reaches 10%. The simulated maximum antenna gain across the operating frequency band is about 12. ldBi. Moreover, in the case of the practical installed height y0 = 2.0 lambda, the simulated gain reaches 16. 27 dBi and the elevation main beam direction is 83.25deg, which is due to the effect of the ground plane.