Design of Inverted “V” Grid Dipole Antenna

Radio astronomy uses antenna array for observation in the HF-VHF frequency band. According to the requirements of SKA (square kilometer array), the gain, structure consistency, stability, impedance change trend, polarization purity and other aspects of each array element antenna need to reach high indicators to meet the requirements of Sun, Jupiter, Epoch of reionization and other measurements in polarization measurement, antenna tracking stability and receiver broadband matching and other aspects. According to the performance requirements proposed in SKA requirement 2165:polarization purity 2135-38 and sensitivity per polarization 2814-15, and after summarizing the experience of the original design, a new type of inverted "V" grid dipole antenna suitable for HF-VHF for the 10-90 MHz frequency band is designed in this study, which has the advantages of light weight and small wind resistance. The structure has the advantages of slow impedance change and good polarization purity in the ultra-wide frequency band of 10-90 MHz. Among them, in terms of impedance change:the real part of the impedance of the antenna changes from about 0.8 Ω to 631.132 Ω, which is better than the low-frequency array antenna of the low-frequency radio array, reducing the difficulty of receiver matching and noise; in terms of polarization purity:the overall axial ratio of the antenna is less than 0.41 dB, with good polarization isolation for strong polarization signals such as solar radio bursts.