Widening The Antenna Band Method

- Dec 14 2017 - (1) traveling wave antenna. The analysis of the symmetric oscillator, because the current dipole on the distribution of standing wave, the impedance bandwidth is very narrow, limiting the symmetric oscillator frequency bandwidth, thus broadening if the dipole impedance bandwidth, it can effectively broaden the dipole band width. According to the transmission line theory, if the matching load is at the end of the conductor, the current distribution on it is traveling wave distribution, and the input impedance is equal to the characteristic impedance of the transmission line, which does not vary with frequency, that is, the broadband impedance characteristic. The antenna on the antenna is called the traveling wave antenna, which is distributed according to the traveling wave. The traveling wave type antenna generally has better unidirectional radiation characteristics, high directional coefficient and wide impedance bandwidth characteristics, so the traveling wave antenna has wide frequency band. The efficiency of the antenna is lower than that of the resonant standing wave antenna because part of the energy is absorbed by the end - connected load. [1]
(2) protruding the angle rather than the length. For example, a spiral antenna avoids a fixed length unit and produces a broadband band. The structure of the infinitely long double cone antenna is only related to angle, but it is independent of finite length. So its radiation and impedance characteristics are independent of frequency, and the bandwidth is infinite. In practice, a non frequency variant antenna can be designed by minimizing the limited length effect and maximizing the angle dependence. [1]
(3) coarse conductor. Increasing the impedance bandwidth of a resonant antenna, such as a vibrator antenna, can increase the bandwidth of the antenna.
(4) self complementing structure. Self complementing features can also lead to non frequency performance. A self complementing structure is a structure that covers its complementary structure precisely by means of translation and (or) rotation. Because the input impedance of the Zin input impedance of Zin antenna and its complementary antenna structure complementary satisfy the relation of Zin*Zin = ETA 2/4 complementary, equals the input impedance of self complementary antenna input of resistance and its complementary antenna therefore, since the input impedance of the antenna is Zin=. The /2 patch is independent of frequency. In free space Zin= 0/2 = 60K = 188.5 (omega). [1]
(5) self proportional structure. For different frequencies, the effective area (radiation area) corresponds to the antenna. For different frequencies, the effective area is different, but the structure related to the electric length remains unchanged. Most of the radiation occurs on the symmetric half wave length of the antenna, or the circumference of the ring part of the wavelength (effective area), such as log periodic antenna, planar spiral antenna and so on. [1]
(6) the band width of the vibrator type antenna is increased by changing the impedance bandwidth of the vibrator type antenna, such as the sleeve antenna.