ELECTROMAGNETIC DETECTION AND IMAGING TRANSCEIVER (EDIT) AND ROADWAY TRAFFIC DETECTION SYSTEM
First Claim
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1. An object detection system, comprising:
- a resonant microwave patch antenna (RMPA) with an active face characterized by responses in its complex input impedance (Zin) and resonant frequency to relative changes in the bulk dielectric constant loading caused by a movement of objects proximate to said active face, wherein the RMPA reacts differently to dielectric changes in its fringing and propagating e-fields according to relative direction;
an automatic control configured to minimize the Zin of the RMPA while a continuous wave (CW) drive is applied to the RMPA by maintaining a state of resonance despite any media variations and movements of said objects proximate to said active face; and
an interpretive device for measuring and interpreting shifts in the input impedances and the phase angles of the RMPA as indications of the sizes, positions, and speeds of objects-of-interest relative to the face of the RMPA.
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Abstract
An automatic frequency control is used to keep a continuous wave (CW) transmission tuned to the resonant frequency of a resonant microwave patch antenna (RMPA). Changes in loading and the bulk dielectric constant of the mixed media in front of the RMPA will affect its resonant frequency and input impedance. A significant shift in the measured input impedance is interpreted as an object moving nearby, and the phase angle of the measured input impedance is used to estimate the direction of an object'"'"'s movement.
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Citations
8 Claims
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1. An object detection system, comprising:
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a resonant microwave patch antenna (RMPA) with an active face characterized by responses in its complex input impedance (Zin) and resonant frequency to relative changes in the bulk dielectric constant loading caused by a movement of objects proximate to said active face, wherein the RMPA reacts differently to dielectric changes in its fringing and propagating e-fields according to relative direction; an automatic control configured to minimize the Zin of the RMPA while a continuous wave (CW) drive is applied to the RMPA by maintaining a state of resonance despite any media variations and movements of said objects proximate to said active face; and an interpretive device for measuring and interpreting shifts in the input impedances and the phase angles of the RMPA as indications of the sizes, positions, and speeds of objects-of-interest relative to the face of the RMPA. - View Dependent Claims (2)
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3. A roadway traffic detection system, comprising:
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a resonant microstrip patch antenna (RMPA) configured to be buried and hidden in a roadway, wherein the RMPA reacts differently to dielectric changes in its fringing and propagating e-fields according to relative direction of objects above its active face; a sensor controller connected to the RMPA to drive the RMPA with a variable frequency, and to measure the impedance and phase (Zin) of the RMPA while keeping the RMPA at frequency resonance; and an interpretive device that deduces particular changes in the resonant frequency, impedance, and phase of the RMPA as the size, direction, and speed of objects passing overhead; wherein, objects near the RMPA affect the dielectric constant and thereby also affect the resonant frequency, impedance, and phase of the RMPA. - View Dependent Claims (4, 5, 6)
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7. A method for detecting movements of objects, comprising:
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radiating an area with a resonant microwave patch antenna (RMPA); maintaining the frequency of a continuous wave (CW) transmission applied to the RMPA in real-time to match the resonant frequency of the RMPA as it changes with variations in its loading; interpreting a minimum in the instantaneous input impedance of the RMPA as an indication of its being operated at its resonant frequency given how it is loaded; and announcing the presence of objects moving nearby by analyzing how the instantaneous input impedance of the RMPA changes over time. - View Dependent Claims (8)
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Specification