Study Of Short Wave Active Loop Antenna And Dual-mode Antenna

With the development of short-wave communication, active receiving antennas have become a research hotspot. Aiming at the short wave field testing instrument for the requirements of the developme nt of antenna, a short wave active receiving loop antenna is designed in this paper. And a dual- mode vehicle antenna used in receiving meteorological satellite signals is proposed in this paper.First of all, this paper compared the loop antenna and the monopole antenna, it is shown that the loop antenna has good characteristics. In order to deal with the received signal, a passive low pass elliptic filter is designed. Using the simulation software-ADS and design software-Filter Solutions, elliptic Filter is realized and simulated. The experimental results show that the antenna meets the user’s requirements.Secondly, a low noise amplifier circuit of short wave band is designed, the bias circuit of the LNA and the input and output matching network are designed. Considering several performance indexes including gain, VSWR, the LNA is further optimized. The testing results of LNA show that the project demand is achieved.At last, a dual- mode vehicle antenna used in receiving meteorological satellite signals is proposed in this paper. A special feed point is adapted to get good impedance matching. The designed antenna has smaller size accompany with good gain and radiation pattern. The measured results show that the gain of the O mni antenna is 4d Bi, and antenna beam is butterfly omni-directional(the main beam has 30 degrees up), the gain of circularly polarized antenna is more than 8dBi.