Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola

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4.6 Loop antenna Figure 4.10. Return loss graph of the folded-patch 2. When the work with the wideband folded-patch antenna was finished we read Perlos patent application SE0403110-0 about a loop antenna. This loop antenna is a narrowband antenna that is tunable over the whole DVB-H frequency band. The work with the loop antennas in section 4.6 is based on this patent. The concept consists of a loop antenna that is tuned by two variable capacitance diodes (see figure 4.11). An analogue voltage controls the diodes, for simplicity the same voltage that controls the tuner in the DVB-H receiver. The inductance between the two diodes prevents the signal from leaking into the control circuit. If there in some way leaks signal through the inductance the capacitance will ground this signal. To be able to feed at the same point as the ground point, which is preferable to get a balanced antenna, the length of the feeding loop can be changed to get the desired performance. 38
Figure 4.11. Loop antenna schematic (measures in mm). The antenna in figure 4.12 is a loop antenna that is designed by Perlos. Its diameter is 30 mm and is made by a 3mm wide metal band. This antenna has a bandwidth of 11 MHz at –6 dB return loss, see figure 4.13 for return loss graph. Figure 4.12. Perlos loop antenna. 39
Page 1 and 2: Design of Antennas for Handheld DVB
Page 3 and 4: Acknowledgements This master thesis
Page 5 and 6: 4 DESIGN AND TESTING OF ANTENNA SOL
Page 7 and 8: Figure 5.2. Reference dipole antenn
Page 9 and 10: 1 Introduction The passed decade th
Page 11 and 12: 2 Background This chapter provides
Page 13 and 14: is simultaneously modulated into 10
Page 15 and 16: 2.1.3 Reed-Solomon Codes 2.1.4 DVB-
Page 17 and 18: 2.1.5 DVB-H DVB-H is the latest dev
Page 19 and 20: 2.1.5.2 Time slicing A large proble
Page 21 and 22: figure 2.5). All three elements tog
Page 23 and 24: symbols or four 2K OFDM symbols. Th
Page 25 and 26: 2.2 Competing standards The DVB-H s
Page 27 and 28: 2.3 Antenna theory This section des
Page 29 and 30: Figure 2.9. Impedance bandwidth def
Page 31 and 32: unloaded quality factor (Q0) and th
Page 33 and 34: losses should be avoided in handhel
Page 35 and 36: 3.3 Loop Figure 3.1. Yagi-Uda anten
Page 37 and 38: PIFA Figure 3.2. Four different con
Page 39 and 40: The size of the antenna is another
Page 41 and 42: 4.4 PIFA To verify the balun a resi
Page 43 and 44: 4.5 Folded-Patch With the PIFA-ante
Page 45: Figure 4.9a. Folded-patch 2, front
Page 49 and 50: Figure 4.15. Wire loop antenna retu
Page 51 and 52: using an H-field antenna together w
Page 53 and 54: antenna. The dimension of the anten
Page 55 and 56: The result of the return loss measu
Page 57 and 58: Figure 4.24. Return loss graph for
Page 59 and 60: The result of the measurement of th
Page 61 and 62: Figure 4.31. Return loss graph for
Page 63 and 64: frequency band, the first from 470
Page 65 and 66: Figure 5.6. Radiation pattern for R
Page 67 and 68: 5.1.3 Measurement result In this ch
Page 69 and 70: Figure 5.10. Radiation pattern for
Page 73 and 74: Table 5.4. Switched monopole 1, gai
Page 75 and 76: Power gain / dB 2 0 -2 -4 -6 -8 -10
Page 79 and 80: was received in all five channels.
Page 81 and 82: 6.3 Control signal 6.4 Cost The swi
Page 83 and 84: not be possible, there will always
Page 85 and 86: There are many advantages with tuna
Page 87 and 88: 8 References [1] Schiller, Jochen -
Page 89: [29] Gardiol, Fred - Microstrip cir

Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola

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