Study Of High-gain Planar Antenna And Its Arrayfor W-band Application

The W-band antenna suffers from such problems as the high loss and the surface wave.Meanwhile,the demand for the high-integration and low-cost antenna system is rising in industrial community.To realize high-gain,high-effciency,high-integration,and high-reliabilitythe planar antennas and arrays of the transmission characteristics of the traditional planar transmission lines and the new type GWGs(Gap waveguide)at W-band are analyzed quantitatively in this thesis.Based on the study results,a high-performance wideband low-loss rectangular waveguide-microstrip transition structure is proposed,which can be used in W-band high-efficiency LTCC packaging antenna system design.Moreover,the high-gain wideband linearly polarized and circularly polarized planar antenna elements are designed using LTCC technology and traditional PCB process,respectively.By combining high-gain antenna elements and low-loss feed networks,the high-gain and high-efficiency antenna arrays are achieved.The main contents are summarized as follows:1.Study of the transmission characteristics of.the traditional planar transmission lines and novel GWG at W-band,and design of the wideband and low-loss microstrip line-rectangular waveguide transition structure:The transmission characteristics of the traditional planar transmission lines are presented.The LTCC-based and PCB-based low-loss GWG transmission lines are proposed to meet the low-loss requirements of the W-band large-scale antenna array feeding networks.To verify the performance of the above GWQ a GWG feeding network is designed.And a SIW(Substrate integrated waveguide)feeding network with the same size of GWG network is also proposed for performance comparison.For the measurement of the W-band transmission integrated components,a wideband and low-loss LTCC transition is presented.Moreover,the synthesis method of the filter is applied to explain the operating principle of this transition;and the corresponding equivalent circuit model and coupling coefficient are demonstrated;and the manufacture tolerances are analyzed.At last,a back-to-back transition module is manufactured and measured to verify the performance.2.Design of high-performance W-band packaging antenna based on LTCC technology:A novel antenna in packaging(AiP)model based on LTCC technology is proposed for the high-integration and high-mechanical-strength packaging application.According to this AiP model,a high-performance LTCC packaging antenna module is designed;and the metal re-packaging is achieved on this module.Through the reasonable design of metal box,it not only solves the shielding problem of the traditional metal packaging,but also enhances the performances of the packaging antenna.The characteristics of wire bonding are analyzed at W-band.Furthermore,a packaging low noise amplifier(LNA)with LTCC technology is achieved at W-band,and the measurement results verify that this packaging has a good performance.Based on the above work,a W-band high-performance active packaging antenna is achieved.This work provides some useful guidance for the design of W-band high-integration antenna system.3.Design of the W-band high-gain LTCC antenna and array with GWG feeding network:A W-band high-gain linearly polarized antenna element with LTCC technology is presented.To enhance the gain of the antenn,an L-probe is designed to excite the substrate-filled metal cavity.A vertical double-layer feeding network composed of GWG and SIW is designed to reduce the dimension of the array plane.This kind of hybrid network can reduce the transmission loss and improve the performance of the antenna array.In addition,a reference antenna array with a feeding network totally composed of SIW is designed for comparison.Some wideband and low-loss transition structures are designed to meet the requirements of the signal transmission between different transmission lines and different layers.On the basis of the linearly polarized antenna mentioned above,a circularly polarized antenna element and its array are achieved by changing the structure of the director.The measured results demonstrate the wide bandwidth and high-gain radiation performance of the proposed two antenna arrays that will be useful in W-band application.4.Design of high order mode cavity excited high-efficiency W-band antenna subarray and its array with GWG feeding network:A low-cost and high-efficiency linearly polarized antenna array is presented.By using the high order mode substrate integrated cavity to excite the slot antenna subarray,the transmission loss caused by divider can be reduce.And it also reduces processing difficulty and fabrication cost.Moreover,the bandwidth and gain of the proposed antenna are improved.For reducing the loss further,the GWG technology is applied to feed the substrate integrated cavity subarrays.For measurement purpose,a wideband and low-loss transition structure between GWG and rectangular waveguide is designed.On the basis of the above linearly polarized antenna subarray,a 2×2 circularly polarized antenna subarray is achieved by loading four L-shaped probes to four rectangular radiation apertures.Combined with a low-loss GWG feeding network,a high-efficiency circularly polarized array is obtanined.The measurement results demonstrate the high-gain and high-efficiency performance of the proposed antennas based on conventional PCB technology.