In case of AA coupling value analyzing, usually the following construction is taken [1] (fig.1): L active transmitters of two–dimensional array are connected to first outcome of emitting subarray beam former (BF1), М emitters are connected to certain secondary radiator (for example, it`s loaded to matched resistance) of decoupling subarray, N secondary radiators are connected to second emitting subarray beam former (BF2). The S2 and S22 scattering matrix choice, then BF1 and BF2 characteristic of active and secondary subarrays [1…3] fixed, is worthy of notice. BF1 and BF2 characteristic influence and mutual coupling magnitude between emitters of emitting and secondary subarrays are of less importance.
Figure 1. Antenna system scheme.
In the article bypassing magnitude calculation results for special cases of gain–phase distribution (GPD) in BF1 and BF2 outcomes are given. It can be gotten if wideband microstrip antenna array (WMAA) [4] would be used as single transmitter–receiver curtain. Suppose that both BF have isolated and matched outputs and decoupling subarray is absent (M = 0). Then coupling coefficient expression looks like this [1]:
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(1) |
where Y12 — dimension matrix 1xN of complex transfer constant coefficients from BF2 outcomes to it`s input; X21 — dimension matrix Lx1 of complex transfer constant coefficients from BF1 input to it`s outcomes; C31 — Toeplitz matrix of coupling coefficients between emitters of emitting and secondary subarrays.
