Switchable Array Antennas for 24 GHz Radar Applications Master Thesis By Bo Zhou 04.09.2012 1
Outline Basic Theory and Concepts Phased Array Antennas Switching Concept Network Distribution and Components Final Design and Analysis Conclusion 2
Radar System Requirements Radar systems transmitter duplexer receiver display antennas 3
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
Network Concepts Feeding Networks Constrained Feeds Semi-constrained Feeds Unconstrained Feeds Series Parallel Beam Forming Network Series Parallel 5 Blass Matrix Butler Matrix
Network Concepts Wilkison power divider Matched corporate feed Parallel constraind feeds 6
Phased Array Antennas Equal phase array Phase increase by φ 7
Elevation distribution (column design) Directivity HOCHFREQUENZTECHNIK Phased Array Antennas Empire model of single column Azimuth distribution 8
Phased Array Antennas Azimuth distribution Determination of the number of columns 8 elements 9
Phased Array Antennas Azimuth distribution 16 elements 10
Phased Array Antennas Azimuth distribution Network Distribution 11
Phased Array Antennas Double use of the antenna seperated with Wilkison power divider 12 Design of the whole network
Phased Array Antennas Simulation of the antenna array Only with ports 13
Phased Array Antennas Simulated farfield patterns Amplitude and phase distribution of the ports Grating lobes 14
Switching Concepts Phase shifters Hybrid coupled phase shifter 15
Switching Concepts Phase shifters 90 hybrid coupler 16 EMPIRE model of phase shifter
Switching Concepts Phase shifters 17
Network implementation Simulation of antenna array Only with ports definition 18
HOCHFREQUENZTECHNIK Network implementation 19
HOCHFREQUENZTECHNIK Network implementation 20
HOCHFREQUENZTECHNIK Network implementation 21
HOCHFREQUENZTECHNIK Final Design 22
HOCHFREQUENZTECHNIK Final Design 23
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
Reference 25
Thank you for attention! 26
Network Concepts Unconstrained Feeds Reflect array 27 Lens array
Network Concepts Beam Forming Network Butler Matrix Series Parallel Blass Matrix Butler Matrix Schematic of Butler matrix 28
Network Concepts Butler Matrix 90 Hybrid couplers Phase shifts in unit 29
Network Concepts Blass Matrix 30
Phased Array Antennas Grating lobes Condition for appearence of grating lobes Phase distributions 31
Switching Concepts Components of phase shifters 32
Switching Concepts Phase shifters 33
Switching Concepts Phase shifters 34
HOCHFREQUENZTECHNIK Final Design 35
Network Concepts Constrained Feeds Series constraind feeds 36
HOCHFREQUENZTECHNIK Switching Concepts 37