1) Periodic measurement of the complex equivalent resistance (pure resistance and image impedance) of the inductor, the value of which depends on the state of the lining (the presence of pits and caverns, thickening of the channel and narrowing of the channel filled with liquid metal, etc.) [10].

Hence the functional dependencies of the inductor resistances (pure resistance Rinput and image impedance Xinput) on the parameters of the secondary liquid-metal circuit [R.sub.2'] and [X.sub.2'] have the following form:

In this linear region, the measured

image impedance, Z", was related to the frequency, f, and the coating capacitance by

1, the coupled line section T and S odd- and even-mode characteristic impedance are [Z.sub.te], [Z.sub.to] and [Z.sub.se], [Z.sub.so] and the image impedance of coupled-line section T and coupled-line section S are [Z.sub.t] and [Z.sub.s].

Secondly, the image impedances [Z.sub.t] and [Z.sub.s] are calculated from Equation (12), and then [Z.sub.to], [Z.sub.te], [Z.sub.so] and [Z.sub.se] are obtained according to Equations (1)-(3).

To understand the structural stop band completely the dispersion data and the image impedance of each of the cells of the log periodic structure are examined.

To overcome this, the variation of image impedance must be minimized.

The dual-feed patch radiator has a cardioid radiation pattern with the maximum in the backfire direction, has an image impedance that remains almost constant from a very low frequency up through the first resonance and has reduced width at resonance to allow more elements in a given space.

This excitation not only yields the cardioid pattern, but produces near-constant image impedance. A slot-excited T|M.sub.01~ mode behaves like a parallel resonant circuit in series with the feeder, and a post-excited T|M.sub.00~ mode is like a series resonant circuit in shunt with the feeder.

The inductances of gate and drain lines are determined from the value of the line

image impedance and [[omega].sub.c].

The wave will be reflected partially at the discontinuity to adapt to these new conditions, mainly to the changed

image impedance.

This implies that the

image impedance of both structures is equal to the reference impedance [Z.sub.0] at [[theta].sub.d].