impedances
at various frequencies on the Smith charts, with computed values
(in full line) and measured values (in doted lines). These charts
underscore the performances of a resonating cavity like a
R, L, C parallel device, and confirm the impedance values computed
by the method of moments.
Figure 4
Figure 5
|
The calculated and measured values are compared at various frequencies
(FIG 6, FIG7)
The bandwidth is measured at VSWR ý 2.5:1
, when the real and the imaginary terms of the impedance
are equal.
Figure
6
Figure
7
The results have validated the antenna equivalent circuit.
This sheme helped to optimize the dimensions of the radiating element,
considering the efficiency and bandwidth requirements. The approximative
values are, from 2 to 12 MHz:
Rr = 0,5m to 3 with a 2,2m2 antenna
surface
Rp= 0.01 to 0.02
C= 3500 to 60 pF
Rc= 0.05 to 2
|