Research And Design Of Low-profile Communication Antenna For Airborne Platform

As a special branch in the field of antenna application,airborne antenna has been widely studied and paid attention to in recent years because of its special value and status.It is particularly noteworthy that looking at the world,in the development background of the carrier platform spanning three generations,equipping the fourth generation,and entering the fifth and sixth generations,the design requirements for the airborne platform antenna are further improved,and the more critical point is that the antenna needs to be conformal design with the carrying platform,and then make it flush with the carrying platform,so that the on-board antenna will not change or even destroy the aerodynamic characteristics of the platform,which means that the antenna needs to have low profile and miniaturization characteristics.Furthermore,according to the actual scenarios and functional requirements,the design requirements for the radiation performance of the antenna are put forward.In view of the above application background,combined with the specific project requirements,this thesis designs several airborne antennas,the main work includes:A low-profile airborne vertically polarized omnidirectional communication antenna based on cone structure was designed.The antenna uses a monopole-like antenna with gradient polyline characteristics to achieve good vertical polarization omnidirectional radiation.It realizes low profile design by short-circuit loading and capacitive loading.The anenna completes the embeded flush installation design of the airborne antenna by loading the back cavity and radome loading.The antenna avoids the use of lumped elements through equivalent loading,simplifies design difficulty,and improves design accuracy through the rational use of radome.After optimized design,the antenna module realizes low profile,broadband,miniaturization design,and has good omnidirectional radiation performance.Finally,in order to verify the rationality of the design,the antenna was prototyped and measured,the test results were in good agreement with the simulation,with an impedance bandwidth of more than 50%and a profile of 0.077λ_max,highlighting its practical application potential in the field of airborne antennas.A low-profile airborne vertically polarized omnidirectional communication antenna based on slot structure was designed.Using the dual idea,the antenna uses the characteristics of a slot that can be equivalent to magnetic current,and its radiation pattern has the potential to realize omnidirectional radiation.By designing the sidewall slots on the metal cylinder,the probe is used to excite the slots,the stable omnidirectional radiation is realized.The design of a low-profile airborne vertical polarization omnidirectional antenna with broadband radiation characteristics is completed by further loading through the metal back cavity and radome.The profile of slot antenna is reduced by 20%compared with the discone antenna.The measured results of the prototype show that the antenna has broadband characteristics and vertical polarization omnidirectional radiation characteristics,with a profile of 0.061λ_max and an impedance bandwidth of more than 50%.An improved low-profile airborne vertically polarized omnidirectional communication antenna based on slot structure has been designed.By improving the number of slot and position arrangement on the cylinder,the omnidirectional radiation characteristics are better optimized and the gain ripple in the horizontal plane is reduced.The improved antenna takes into account the characteristics of low profile,broadband,and good roundness performance.The measured results of the prototype show that the roundness of the antenna in the wideband range is improved,and the impedance bandwidth and profile are consistent with the previous version.