Research On Multi-band And Miniaturized Automotive Active Antenna Based On Negative Impedance Convertor

With the rapid development of wireless communication in automotive application, the requirement of miniaturized and multi-band automotive antenna design becomes higher and higher. Because the performance limitation of the electrically small antenna, engineers start to look for the approach to design the active antenna in an ultra-small package.In this thesis, each portion of active Electrically Small Antenna’s theory are introduced, including passive antenna, Low Noise Amplifier and Non-Foster Negative Impedance Convertor for wideband matching, the HFSS EM simulation tool also has been used in the antenna design, and the antenna prototype sample is built and measured, a multi-band small size active antenna was successfully designed for automotive application.The critical design parameters and optimization method for the active ESA antenna has been introduced in this thesis. The antenna height was only 55 mm about 1/60λ of FM band and 1/30λ of DABIII and DMB band. The active average Gain in elevation 0 degree is better than 5dBi in FM band, and better than 7d Bi in DABIII and DMB band. The Low Noise Amplifier Noise Figure better than 2.5dB at FM band and better than 2.0dB at DABIII and DMB band, delta IM3 better than 59 dB at FM band and better than 32 dB at DABIII and DMB band. Finally, the antenna was successfully matched with Low Noise Amplifier in the wide bandwidth through VINIC technology, the active antenna Gain bandwidth was improved significantly.This new designed antenna performance is better than traditional whip styling and glass-printed antenna for automotive applications, it can be integrated in the Shark-fin styling.