| Phased array antenna has been widely used in radar systems,wireless communication systems and other communication fields for its capacity of beam-forming and fast scanning.With the increase of the types of radar observation targets and the rapid development of wireless communications in the past decades years,the development of broadband,wide-angle scanning and shared aperture phased array antenna is significantly promoted.Through the research and analysis of wideband array elements,we design two types of wideband phased array that work independently and one shared aperture phased array for wideband and co-aperture phased array applications.Firstly,an equivalent circuit model of tightly coupled dipole array(TCDA)is introduced.According to the working mechanism of tightly coupling dipole array,a method of adding a resistive frequency selective surface(FSS)in the middle position of the array and the ground plane to absorb the antiphase electromagnetic waves reflected by the ground plane.It has been proven to significantly broaden the bandwidth of the array.For the fabrication of resistive FSS,we use lumped resistors connected in series as a ring to replacing the resistive FSS,the performance of these two types resistive FSS shown great aggrement in full wave simulation.An ultrawideband linear tightly coupled dipole array with a resistor-loaded FSS is designed and the linear array is constructed along E-plane.The final linear array with the resistor-loaded FSS achieves 8.6:1(0.37-3.2 GHz)bandwidth(VSWR<3)when scanned to ±45o in E-plane.In the second section,a wideband phased array based on triangular lattice arrangement is investigated.The aim is to solving the problem of small element spacing in the traditional wideband phased arrays' design.In this section,the ultimate scanning angle in airspace and typical scan blindness for large element spacing array in triangular lattice arrangement is analyzed.Based on a connected cavity antenna element,a triangular lattice arrangement phased array operating at 7 – 13 GHz with large element spacing is designed to investigate its scanning performance.In order to suppress the scan blindness observed in the operating frequency band,a method of using EBG to suppress the scan blindness is proposed which has been proven to have great effect.The simulated results of infinite array element shown that it can scan to ±60° both in E-and H-plane with VSWR ? 3.A 13 × 5 finite array prototype is fabricated for experimental verification,the measured results of the finite array is consistent with simulated one.Finally,a novel shared aperture antenna array based on the wideband elements studied in previous is investigated.For the shared aperture antenna array,the connected cavity element is selected for low frequency band and high frequency band antenna is a tightly coupled dipole array.The presented antenna array operates in P-band for horizontal polarization and S-band for vertical polarization.An infinite shared-aperture array element is simulated,the results shown that the array can achieve bandwidth of 35.3% and 25.8% at P-and S-band,respectively.Beam-scanning ranges of P-and S-band array are both satisfied ±20o in vertical plane and ±60o in azimuth plane with active VSWR<2.5. |
PDF Full Text Request