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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

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