| Compared with low-frequency range Millimeter wave band(30~300 GHz)has the advantages of wide bandwidth,small component electric size,good communication security,high resolution ratio to object identification,and so on,which is become research focus point recent years.In W band(30~300GHz),especially at 94 GHz frequency range has the lowest atmospheric attenuation,which is suit for point to point communication and is widely chosen for working frequency band of the ground-based radar and air-to-air missile radar,ect..However,with the improvement of frequency,the dielectric loss and ohmic losses will incresase,the conventional planar transmission lines such as microstrip line is not suitable for working in W band,waveguide structure has low loss,but it is huge and it is difficult to integrated with planar circuits.Substrate Integrated Waveguide possesses the advantages of the microstrip line and waveguide,which has been widely used in the design of millimeter wave planar circuit.In some special application field,it is required that the received signal of the antenna with high signal-to-noise ratio to reduce outside interference.In order to reduce the received noise of antenna,the most effective method is lower the sidelobe level of the antenna pattern.However,because of the short wavelength in W band lead to high precision of antenna design and fabrication are required,it is difficult to design antenna array with low sidelobe level in W band.Many antenna array with low sidelobe level design methods at low frequency range are not suitable for W band,at present,there are few research about W band antenna array with low sidelobe level.Aiming at the characteristics of design difficulty of antenna array with low sidelobe level in W band,this paper is based on SIW transmission line and has in-depth study on W band antenna array with low sidelobe level,mainly includes the following aspects:Firstly,studying about the characteristic of a single SIW slot antenna that operating at W band,and extracting the admittance parameters of the single slo t at different offset and length of the slot.Then,the design method of SIW slot array antenna with low sidelobe level in H plane is studied,a 1×32 antenna array with low sidelobe level in H plane is designed and simulated.At the same time,in order to realize the antenna array with low sidelobe level on E plane,the comb shape and tree shape unequal power dividers with phase balance are studied.Due to the comb shape dividers and conventional design methods of tree shape dividers are not suitable for designing in W band,based on this puts forward,a novel kind of power divider with phase balance is proposed,which is not limited by the frequency.In order to reduce aperture size of the antenna,a waveguide to SIW hybrid integrated E plane divider is pre sented and designed.Finally,a 93~95GHz antenna array is designed and fabricated,the array size is 16×32,the sidelobe level of E plane and H plane are both under-20 dB,the simulated and measured results are in good agreement.Then after that,aiming at the situation that the design of the circular polarization antenna array with low sidelobe level is difficult,combing with the characteristic that the planar long slot antenna is easy to realize shared aperture,b y designing the two orthogonal linear polarization antenna array with low sidelobe level,realized the radiation pattern of circular polarization antenna array with low sidelobe level in two orthogonal plane,and give out corresponding operation principle.Based on the put forwards,a 93.5~94.5GHz shared-aperture low sidelobe level dual-CP SIW parallel-plate slot array antenna is designed.The measured result s validate the correctness of the designed one. |
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