In this licentiate thesis the implementation of small internal DVB-H antennas for handheld multisystem radios is studied, and several prototypes and simulated designs are presented and evaluated.Since the volume that can be reserved for antennas is very restricted, the limits for the size of capacitive coupling element based antenna structures inside handsets of different size were studied. The results indicate that the smallest required volume of the coupling element which ensures sufficient performance in today's typical-size monoblock mobile handsets would be about 3 - 4 cm3. Instead, for tablet-size and open clamshell-size terminals the antenna element are shown to be significantly smaller and thinner. Direct-feed-based structures can provide very low profile antenna solutions for tablet and clamshell-type terminals.The effect of the user on performance of the DVB-H antenna was studied for some cases. Maximum of 5 - 9 dB decrease in the total efficiency was shown and thus the effect of the user seems to be a significant challenge for the operation of DVB-H. Relatively low isolation, about 18 dB, between the DVB-H and GSM900 antennas was demonstrated and thus the interoperability of DVB-H and GSM900 systems seems impossible without additional filtering.
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