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Transkript

1 Switchable Array Antennas for 24 GHz Radar Applications Master Thesis By Bo Zhou

2 Outline Basic Theory and Concepts Phased Array Antennas Switching Concept Network Distribution and Components Final Design and Analysis Conclusion 2

3 Radar System Requirements Radar systems transmitter duplexer receiver display antennas 3

4 Radar System Requirements Automotive or security applications High resolution Not only range, speed But also angular position Small size Low cost flexable... 4 beams Narrowbeam High directivity (more than 20dB) Good isolation between beams (at least 3dB) 4

5 Network Concepts Feeding Networks Constrained Feeds Semi-constrained Feeds Unconstrained Feeds Series Parallel Beam Forming Network Series Parallel 5 Blass Matrix Butler Matrix

6 Network Concepts Wilkison power divider Matched corporate feed Parallel constraind feeds 6

7 Phased Array Antennas Equal phase array Phase increase by φ 7

8 Elevation distribution (column design) Directivity HOCHFREQUENZTECHNIK Phased Array Antennas Empire model of single column Azimuth distribution 8

9 Phased Array Antennas Azimuth distribution Determination of the number of columns 8 elements 9

10 Phased Array Antennas Azimuth distribution 16 elements 10

11 Phased Array Antennas Azimuth distribution Network Distribution 11

12 Phased Array Antennas Double use of the antenna seperated with Wilkison power divider 12 Design of the whole network

13 Phased Array Antennas Simulation of the antenna array Only with ports 13

14 Phased Array Antennas Simulated farfield patterns Amplitude and phase distribution of the ports Grating lobes 14

15 Switching Concepts Phase shifters Hybrid coupled phase shifter 15

16 Switching Concepts Phase shifters 90 hybrid coupler 16 EMPIRE model of phase shifter

17 Switching Concepts Phase shifters 17

18 Network implementation Simulation of antenna array Only with ports definition 18

19 HOCHFREQUENZTECHNIK Network implementation 19

20 HOCHFREQUENZTECHNIK Network implementation 20

21 HOCHFREQUENZTECHNIK Network implementation 21

22 HOCHFREQUENZTECHNIK Final Design 22

23 HOCHFREQUENZTECHNIK Final Design 23

24 Conclusion Different network concepts and switching concept are discussed Phase shifters with PIN diode are simulated, fabricated and measured The whole RF circuit is simulated The radar system requirements are fulfilled The PIN-diodes switching circuits will more detailed analyzed in near future 24

25 Reference 25

26 Thank you for attention! 26

27 Network Concepts Unconstrained Feeds Reflect array 27 Lens array

28 Network Concepts Beam Forming Network Butler Matrix Series Parallel Blass Matrix Butler Matrix Schematic of Butler matrix 28

29 Network Concepts Butler Matrix 90 Hybrid couplers Phase shifts in unit 29

30 Network Concepts Blass Matrix 30

31 Phased Array Antennas Grating lobes Condition for appearence of grating lobes Phase distributions 31

32 Switching Concepts Components of phase shifters 32

33 Switching Concepts Phase shifters 33

34 Switching Concepts Phase shifters 34

35 HOCHFREQUENZTECHNIK Final Design 35

36 Network Concepts Constrained Feeds Series constraind feeds 36

37 HOCHFREQUENZTECHNIK Switching Concepts 37