Microwave Induced Thermoacoustic Tomography Summer II

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Microwave Induced Thermoacoustic
TomographySummer II

• By Zaid Al-Husseini
• Date 05/27/2005

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Sections

• Current Progress
• Linear EM Time Domain Signal
• EM Frequency Domain Spectrum
• Equipment
• Power Requirements
• Current Experimental Design
• Problems/Concerns and Future Plans

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Current Progress

• Was successful in combining Network Analyzer,
  function generator and MUX in transmitting and
  receiving a pulsating microwave signal with a 30
  duty cycle and having a frequency of 10 Hz (100
  ms period)
• Future experiments will transmit the NA signal at
  1 MHz (1 µs) or higher with a duty cycle of 5.
• Successfully ordered an ultra high frequency
  transducer V304 Panametrics (should be arriving
  Tues/Wed)
• Called Panametrics regarding a pulse amplifier
  5072 PR (cost is 2800 will cost 2520 after
  university discount)
• It is possible to order a Demo Version of
  Amplifier for 2-3 week period.
• Experimental set up was modified based on recent
  findings in order optimize power output, cost
  efficiency and overall quality.

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Linear EM Time Domain Signal
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EM Frequency Domain Spectrum
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Equipment

• V304 Transducer by Panametrics operates at a
  center frequency of 2.25 MHz and it is
  non-focused and Wide Angled (will pick up more
  signals for better imaging)
• Pulse Amplifier by Panametrics operates at a Max
  BW of 1kHz-35 MHz and costs approximately 2520
• We can replace Analog to Digital Converter with
  Oscilloscope (which would connect to the
  computer) as was the case in the Wang et al.
  experiments.
• Will be needing a Power Amplifier and Divider to
  transmit microwave signal at approximately 5 kW
  strength, and the Amplifier should be placed
  between Divider and MUX.
• Divider will transmit EM signal to 4 different
  patch Antennas around the Apparatus

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Power Requirements

• Horn Antenna was used in Wang et al. experiments.
• The Max power output _at_ 3 GHz was 10kW (8.2
  mW/cm2) (Wang et al)
• The Max power output _at_ 9 GHz was 25kW (22.1
  mW/cm2) (Wang et al)
• Thus we will need approx. 5kW _at_ 1.555 GHz (Large
  Patch Antennas)
• Kruger et al. group used 25 kW UHF generator with
  1.0 ms pulse width operating _at_ 500 Hz (2 ms
  period) giving avg. power of 12.5 W during
  imaging.

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Current Experimental Design
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Problems/Concerns and Future Plans

• Power Amplification (5kW) may destroy coaxial
  cable or create a lot of heat.
• We currently only have 2 large patch Antennas we
  need two more for our design
• The pulse amplifier is costly (2500), however we
  can order it for a Demo period (2-3 weeks if
  desired)
• How to connect Oscilloscope to Computer?
• We will need to purchase equipment to construct
  apparatus (ie. Power Amplifier, Divider, pulse
  amplifier, Wood, plastic container, Sample
  material)