Phase shift detector process for making and use of same
Inventors
Cheung, Kin P. • RYAN, JASON T. • Campbell, Jason
Assignees
National Institute of Standards and Technology NIST • United States Department of Commerce
Publication Number
US-10247814-B2
Publication Date
2019-04-02
Expiration Date
2036-01-14
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Abstract
A phase shift detector includes: an interferometer; and a microwave probe in electrical communication with the interferometer, the microwave probe including: a primary shield electrode; and a transmission electrode disposed proximate to the primary shield electrode, the transmission electrode and the primary shield electrode being exposed and arranged to produce an electric field, wherein the transmission electrode is isolated electrically from the primary shield electrode.
Core Innovation
The invention is a phase shift detector comprising an interferometer and a microwave probe in electrical communication with the interferometer. The microwave probe includes a primary shield electrode and a transmission electrode disposed proximate to the primary shield electrode, with the transmission electrode being electrically isolated from the primary shield electrode. The transmission electrode and the primary shield electrode are arranged and exposed to produce an electric field in response to receipt of sample microwave radiation by the transmission electrode. A secondary shield electrode is also disposed proximate to the transmission electrode, with the transmission electrode interposed between the secondary shield and primary shield electrodes, and electrically isolated from both.
The detector uses the interferometer to receive microwave radiation and produce an interferometer signal. The interferometer includes components such as a power splitter, a reference arm with a phase shifter, a sample arm with an attenuator, and a power combiner. The microwave probe receives sample microwave radiation from the interferometer's sample arm and produces probe microwave radiation in response to a sample subjected to the sample microwave radiation. The interferometer signal reflects the balance between the reference arm and the sample arm, which is influenced by the interaction of the microwave probe's electric field with the sample, for example, due to changes in the effective dielectric constant of the sample.
The problem being solved relates to achieving extreme sensitivity in detecting phase shifts in the microwave region, particularly addressing the difficulty in balancing interferometer arms for shorter wavelengths such as optical waves. Conventional bridged instruments and prior detectors have limited sensitivity and balancing capability. The invention overcomes these issues by providing a phase shift detector operating over microwave frequencies from 300 MHz to 300 GHz, that offers financial compactness, high sensitivity, and dispersion compensation. It achieves a better electrical balance between the reference and sample arms through the exposed shield and transmission electrodes, improving sensitivity significantly compared to previous systems.
Claims Coverage
The patent contains two independent claims focusing on the structure and configuration of the phase shift detector and microwave probe within the interferometer system.
Phase shift detector with specific electrode configuration
A phase shift detector comprising an interferometer and a microwave probe having a primary shield electrode, a transmission electrode proximate to but electrically isolated from the primary shield electrode, and a secondary shield electrode with the transmission electrode interposed between and electrically isolated from both shield electrodes, all exposed and arranged to produce an electric field in response to sample microwave radiation.
Interferometer with defined arms and components in combination with the microwave probe
A phase shift detector comprising an interferometer including a power splitter, a reference arm with a phase shifter, a sample arm with an attenuator, and a power combiner, combined with a microwave probe disposed on a dielectric substrate having a primary shield electrode, a secondary shield electrode opposing the primary shield electrode, and a transmission electrode interposed and electrically isolated from both shield electrodes.
The claims cover the inventive configuration of a microwave probe with electrically isolated and arranged electrodes producing an electric field for phase shift detection integrated into an interferometer featuring specific components like splitter, phase shifter, attenuator, and combiner that together provide enhanced phase shift detection capability.
Stated Advantages
Achieves extreme sensitivity in millimeter wave to radio wave range.
Provides orders of magnitude better balance between sample arm and reference arm compared to conventional instruments.
Offers dispersion compensation to reduce background noise and increase detector sensitivity.
Enables compact-sized system operating from 300 MHz to 300 GHz suitable for high precision measurements.
Documented Applications
Use in Fourier transform infrared spectroscopy by propagating infrared radiation through the electrode gaps of the microwave probe.
High spatial and temporal resolution temperature measurement and thermometry of samples with sensitivity around 0.001 °C and spatial resolution on the order of micrometers.
Acoustic probe application to detect local vibrations or distance changes with high distance sensitivity (e.g., 0.1 nm) and temporal resolution for sample analysis.
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