Han, Jeongwoo (2003-05). Development of an electronically tunable ultra-wideband radar imaging sensor and its components. Doctoral Dissertation. Thesis uri icon

abstract

  • Novel microwave transmitter and receiver circuits have been developed for implementing UWB (Ultra-Wideband) impulse radar imaging sensor operating in frequency band 0.2 to 4 GHz. with tunable operating frequency band. The fundamental system design parameters such as the required transmitting pulse power and the pulse duration were estimated for a presumed specific application, the pavement assessment. The designed transmitter is the tunable monocycle pulse generator with tuning capability for the output pulse duration from 450- to 1200- ps, and has relatively high transmitting pulse power from 200 to 400 mW. Tuning of the pulse duration was implemented by novel PIN diode switch configuration and decoupling circuit, and boosting of transmitting pulse power was made possible by using a high power pulse driving circuit and SRD coupling circuit. The synchronous sampling receiver system was designed by using the integrated sampling mixer and two reference clock oscillators placed in the transmitter and receiver respectively for timing control. A novel integrated CSH (Coupled-Slotline Hybrid)sampling mixer has been developed along with the design of the strobe pulse generator appropriate for the impulse radar system. The integrated sampling mixer has unprecedented conversion loss of 2.5 dB for the pulse signal, bandwidth 5.5 GHz, and dynamic range 50 dB. The introduced UWB LNA (Low Noise Amplifier) design operating up to 4 GHz should be useful for weak signal detection applications. The design of the UWB microstrip quasi-horn antenna was optimized for short pulse transmission with respect to the input return loss and the pulse stretching effect. For signal detection in the signal processing stage, the background subtraction technique and B-scan data format were used. A novel signal monitoring technique was introduced in the signal processing to compensate the frequency modulation effect of the reference clock. The test results for the complete system with respect to some sample multi-layer structures shows good receiving pulse waveform with low distortion, enough pulse penetration depth for 13?? pavement sample structure, and minimum 1-in of range resolution.
  • Novel microwave transmitter and receiver circuits have been developed for
    implementing UWB (Ultra-Wideband) impulse radar imaging sensor operating in
    frequency band 0.2 to 4 GHz. with tunable operating frequency band. The fundamental
    system design parameters such as the required transmitting pulse power and the pulse
    duration were estimated for a presumed specific application, the pavement assessment.
    The designed transmitter is the tunable monocycle pulse generator with tuning capability
    for the output pulse duration from 450- to 1200- ps, and has relatively high transmitting
    pulse power from 200 to 400 mW. Tuning of the pulse duration was implemented by
    novel PIN diode switch configuration and decoupling circuit, and boosting of
    transmitting pulse power was made possible by using a high power pulse driving circuit
    and SRD coupling circuit.
    The synchronous sampling receiver system was designed by using the integrated
    sampling mixer and two reference clock oscillators placed in the transmitter and receiver
    respectively for timing control. A novel integrated CSH (Coupled-Slotline Hybrid)sampling mixer has been developed along with the design of the strobe pulse generator
    appropriate for the impulse radar system. The integrated sampling mixer has
    unprecedented conversion loss of 2.5 dB for the pulse signal, bandwidth 5.5 GHz, and
    dynamic range 50 dB. The introduced UWB LNA (Low Noise Amplifier) design
    operating up to 4 GHz should be useful for weak signal detection applications.
    The design of the UWB microstrip quasi-horn antenna was optimized for short pulse
    transmission with respect to the input return loss and the pulse stretching effect. For
    signal detection in the signal processing stage, the background subtraction technique and
    B-scan data format were used. A novel signal monitoring technique was introduced in
    the signal processing to compensate the frequency modulation effect of the reference
    clock. The test results for the complete system with respect to some sample multi-layer
    structures shows good receiving pulse waveform with low distortion, enough pulse
    penetration depth for 13?? pavement sample structure, and minimum 1-in of range
    resolution.

publication date

  • May 2003