High-frequency Antenna

Although this is the era of solid state semiconductor devices in the 21st century, vacuum devices are still great and extensively employed in certain areas for applications while their solid state counterparts are not able to compete as far as delivering the required frequency at microwave to millimeter wavelengths, so many microwave devices have been produced. Researching on high power microwave can be traced back to the early 50's century, because there is a broad prospect of the application on its military and civilian, which has been attached great importantly by many countries. The high-power microwave received the assembly and a wide range of applications whether in communications, radar, navigation, or in scientific research, industrial and agricultural production. Military and scientific research on the higher peak power, higher frequency microwave sources with high power microwave requirements make the development by leaps and bounds 70 years letter in the last century. On high power microwave research and exploration, not only contains the new generation of microwave theory, the new device development work also includes the application of high power microwave research,which promotes the development of radiation technology.Well-known, the high-frequency microwave radiation of high power microwave technology is an extremely important part of determining whether an effective radiated microwave, while making most of the energy applied to the target. Traditional antenna technology has been developed quite mature, and many of the traditional antenna technology can be directly applied to high-frequency microwave antenna. However, the current high power microwave (high power microwave gyrotron TM01, etc.) are symmetrical geometry, the final output models are axially symmetric circular waveguide mode that TM0n mode, TE0n mode, this mode without a very determined direction, and the radiation was not an ideal shaped hollow.If the antenna outputs such a mode that is directly incentived , there will be a big problem about the gain and low energy dispersion., The radiation system should be redesigned in order to obtain the ideal antenna . 1. Because of ordinarily conical horn being used for the radiation of the TE1 1 mode, it exists much of the defect for the radiation of TM0 1mode, In order to construct a antenn -a that radiates a boresight peak (along the longitudinal axis of the source) with high–ga -in beam, high-power capability and small dimension, one prototype dielectric lens an -tenna is proposed, the medium which adopts in the form of sectors is loaded on the front-end of the conical horn antenna, dielectric Lens can compensate the phase, in ord -er to impove the directivity of antennas. In this paper, the analysis from HFSS softwa -re shows that the ku-band dielectric lens antennas have a good directivity and high -gain.2. Because of ordinarily pyramidal horn antenna being used for the radiation of the TE1 1mode, In order to construct a antenna that radiates a boresight peak (along the longitudinal axis of the source)with high-gain beam, high-power capability and good main lobe on 3dB and Cross polarization losses ,one pyramidal horn antenna with corrugations is proposed, the corrugations which adopts in the form of the rectangle is loaded in the part of the horn, reducing spillover efficiency and cross polarization losses , impoving the directivity of antennas,also. In this paper, the analysis from HFSS software shows that the 20GHz pyramidal horn antenna with corrugations have a good low-SLL and high-gain.3. In order to construct a antenna that radiates omnidirectionally, low-loss and good feed structure ,one double-sided patch antenna is proposed, each sided patch share a common ground plane, The results show that absolute bandwidth of the designed antenna is about 3 GHz with return loss-less than -10 dB. The analysis from CST software shows that the Ku-band omnidirectional antenna in the E-plane beam-width is 43. 50 ~77.10 and H-plane roundness is 1dB . Meet the requirements of topic group.