^{0}of principal plane and frequency band with contact ratio no less than 2, increase means much. At that essential bypassing magnitude between receiving AA outcome and transmitting AA input can reach -100…-130 dB.

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 (BF_{1}), *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 (BF_{}2). The *S*_{2} and *S*_{22} scattering matrix choice, then BF_{1} and BF_{2} characteristic of active and secondary subarrays [1…3] fixed, is worthy of notice. BF_{1} and BF_{2} 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 BF_{1} and BF_{2} 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]:

(1) |

where *Y*_{12} — dimension matrix 1x*N* of complex transfer constant coefficients from BF_{2} outcomes to it`s input; *X*_{21} — dimension matrix *L*x1 of complex transfer constant coefficients from BF_{1} input to it`s outcomes; *C*_{31} — Toeplitz matrix of coupling coefficients between emitters of emitting and secondary subarrays.