Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola
Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola
Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola
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Since the measurements <strong>for</strong> the prototypes and the reference antennas are made<br />
<strong>for</strong> the same number <strong>of</strong> points in the sphere we can compare TRP directly to<br />
calculate the efficiency (see equation 5.4) [28].<br />
Prad,<br />
prototype TRPprototype<br />
e 0 =<br />
⋅ 0.<br />
9 =<br />
⋅ 0.<br />
9<br />
(5.4)<br />
P<br />
TRP<br />
rad,<br />
reference.<br />
antenna<br />
reference.<br />
antenna<br />
Where 0.9 is the estimated efficiency <strong>for</strong> our reference antenna.<br />
To calculate the power gain and efficiency <strong>for</strong> our prototypes, we have to measure<br />
and calculate received signal strength and TRP <strong>for</strong> all four antennas. To get more<br />
accurate calculations all measurements was made three times and a mean value<br />
was calculated (see table 5.1).<br />
Table 5.1. Reference antenna values <strong>for</strong> calculation <strong>of</strong> gain and efficiency.<br />
Frequency /MHz Received signal<br />
strength /dBm<br />
TRP /mW<br />
470 -47.9 0.00351<br />
490 -47.3 0.00426<br />
510 -47.0 0.00473<br />
530 -45.9 0.00491<br />
550 -44.7 0.00644<br />
570 -44.0 0.00795<br />
590 -43.7 0.00972<br />
610 -42.8 0.01167<br />
630 -42.4 0.01156<br />
650 -43.5 0.0092<br />
670 -43.2 0.00836<br />
690 -43.4 0.00868<br />
710 -44.5 0.00791<br />
58