On the role of substrate loss tangent in the cavity model theory of microstrip patch antennas

The effective loss tangent (/spl delta//sub eff/) plays an important role in the improved cavity model of microstrip patch antennas. It is calculated using an iterative procedure. Results are presented here showing that the final value of /spl delta//sub eff/ is quite sensitive to the value chosen at the start of the iterative process, i.e., the substrate loss tangent (tan /spl delta/). Since the input impedance depends on /spl delta//sub eff/, it is important to specify the value of tan /spl delta/ in any comparison with experiment.<
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