where the elements of [Z.sub.mn] represent the mutual impedance
between the sinusoidal current elements m and n , [V.sub.m] is the voltage in each segment m which is different from zero only at the position of the voltage source, and [[DELTA].sub.m] = 1/2([[DELTA]l.sub.m] + [[DELTA]l.sub.m+1]).
[Z.sub.m] represents the mutual impedance
between the ground wire and the faulted phase conductor, per span.
(12c), the expression for this new mutual impedance
Carberry, "A technique to simulate the self and mutual impedance
of an array," IEEE Trans.
The active element patterns have a specific relationship with mutual impedance
matrices in array antennas.
Away from having naturally decoupled antennas, a decoupling [lambda]/4 or 3[lambda]/4 transmission line connected between matched, coupled two antennas at specific distances from the antennas input ports, where the equivalent mutual impedance
observed is pure imaginary, is a solution proposed in .
The first is the modulation of the reflected impedance [DELTA][Z.sub.I] by changing the burden impedance [R.sub.II] of the body; the second is similar modulation, obtained by changing the mutual impedance
[M.sub.I,II] between the body and the inductor.
resistivity method (Keller and Frishknecht, 1966) and measurements of mutual impedance
of loop antennas working at the high frequency.
Such geometrical and material considerations in realizing closely proximal antennas with minimum mutual impedance
consideration need a careful design strategy.
According to the circuit theory, the mutual impedance
between two loops can be defined as
The inner electronic field distribution of patch antenna is clearly known, so it is appropriate to be used to calculate the coupling efficiency which has been analyzed in many papers including radiation pattern and mutual impedance
is the array admittance matrix  (here, subscripts R and T were omitted for simplicity), [Z.sub.0] the characteristic impedance of the transmission line connected to each antenna, [[??].sub.m] the matching impedance of each antenna, and Z the mutual impedance