Microstrip Patch Antennas for Broadband Indoor Wireless Systems ...

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Wave propagation E field 3.1.2 Circular Polarization H field Fig 2: Linear Polarization Circular polarization (CP) is usually a result of orthogonally fed signal input. When two signals of equal amplitude but 90 o phase shifted the resulting wave is circularly polarized. Circular polarization can result in Left hand circularly polarized (LHCP) where the wave is rotating anticlockwise, or Right hand circularly polarized (RHCP) which denotes a clockwise rotation. The main advantage of using CP is that regardless of receiver orientation, it will always receive a component of the signal. This is due to the resulting wave having an angular variation. Wave Propagation (LHCP/ RHCP) 3.2 BANDWIDTH Fee d Square Patch Fig 3: Circular Polarization Orthogonal Input Couplar The bandwidth of the patch is defined as the frequency range over which it is matched with that of the feed line within specified limits [4, pg 11]. In other words, the frequency range over which the antenna will perform satisfactorily. This means the channels have larger usable frequency range and thus results in increased transmission. The bandwidth of an antenna is usually defined by the acceptable standing wave ratio (SWR) value over the concerned frequency range. The fig 4 shows a typical broadband phenomenon in terms of frequency band usage. 4
Fig 4: Narrowband vs. Broadband Most commercial antennas use a 1.5:1 ratio, as shown in fig 5, suggesting that the range that is covered between the SWR of 1 up to 1.5 is the bandwidth. To ensure comparability with the commercial products, a decision was made to use a 1.5:1 ratio to calculate the bandwidth of antennas. Fig 5: Bandwidth Measurement 5
Page 1 and 2: Depart of Electrical & Electronics
Page 3 and 4: ORIGINALITY DECLARATION This report
Page 5 and 6: TABLE OF CONTENTS Page no 1.0 Intro
Page 7 and 8: 1.0 INTRODUCTION Currently there is
Page 9: 3.0 FOUNDATIONS FOR MICROSTRIP DESI
Page 13 and 14: 4.0 DESIGN METHODOLOGY In order to
Page 15 and 16: extra copper from the substrate, th
Page 17 and 18: Patch length of 29.66 mm was determ
Page 19 and 20: 6.0 PHASE II 6.1 BROADBANDING SCHEM
Page 21 and 22: 6.3 RECTANGULAR BROADBAND ANTENNA L
Page 23 and 24: VSWR 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.
Page 25 and 26: evident from the BLACK plot in the
Page 27 and 28: 7.0 PHASE III 7.1 AREA COVERAGE MEA
Page 29 and 30: 8.0 ISSUES TO CONSIDER FOR FUTURE R
Page 31 and 32: above in section 9.1, substrates wi
Page 33 and 34: 11.0 REFERENCE [1] Bahl, I. J and B
Page 35 and 36: APPENDIX B: - DIMENSIONS OF RECTANG
Page 37 and 38: Visual illustration showing the ind
Page 39 and 40: APPENDIX E: - BROADBAND RECTANGULAR
Page 41 and 42: APPENDIX F: - NARROWBAND TRIANGULAR
Page 43: APPENDIX H: - BROADBAND ANTENNA COM

Microstrip Patch Antennas for Broadband Indoor Wireless Systems ...

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