Optimization of a broadband phased array with vibrator emitters
The article studies the issue of matching antenna arrays (AA), consisting of vibrators and cross vibrators, located above the final metal screen at a height of ≈ λ/4. This matching is performed within the frequency range of ±10% and scanning angle of ± 60°. Vibrators are powered by ideal oscillators with controlled impedance, located between the vibrator arms. At the first stage, a comparison of “blinding” properties in planar and linear AAs is performed. The results of comparison revealed that “blinding” manifested itself more strongly in flat AAs. At the second stage, the AA configuration is selected to mitigate “blinding” effect. Since “blinding” appears only in the E-plane, and depends on the distance between the vibrators, the best location option is to turn the emitters at an angle of 45° to the edges of the AA. In the third stage, the optimal emitter option is selected. Emitters with straight arms, sloping arms, and pins of sundry heights between these types of emitters are compared. The largest minimum width of the array pattern over the gain antenna pattern within the frequency range and radiation level along the screen, which should be no less than -10 dB. The best characteristics are demonstrated by the grid of vibrators with straight arms and pins of 0.225 λav for both vibrator and cross vibrator AAs. At the last stage, the selected variant is optimized for the height above the screen, arm length and generator resistance. The gain level equal to 0 dB is selected as an optimization criterion. The direction pattern width at gain of 0 dB within the frequency range of ±10% was no less than 118.4° for vibratory AA, and 118.2° for cross-vibratory AA. Maximum SWR value within the frequency band in the scanning range of the vibratory AA was 3.3 The width of the beam along the 0 dB be realized gain in the frequency range of ± 10% was not less than 118.4° for the vibratory AR and 118.2° for the cross-vibratory AA. The maximum value of the SWR in the frequency band in the scanning range in the vibrator AA was 3.3. For the cross-vibratory AA, maximum SWR value was 3.3 as well.