Dosimeter powered by passive RF absorption
First Claim
1. A method for determining an amount of radiation, the method comprising:
- receiving the amount of radiation by a dosimeter, the dosimeter comprising a circuit, the circuit having a resonant frequency that is configured to change according to the amount of radiation received by the dosimeter, wherein the circuit comprises a varactor, the varactor comprising;
a silicon substrate; and
a dielectric layer located on top of the silicon substrate, wherein the amount of radiation causes a corresponding negative charge to build up in the dielectric layer, and the negative charge in the dielectric layer causes a depletion region to form in the silicon substrate underneath the dielectric layer, and wherein a capacitance of the varactor is reduced in response to the formation of the depletion region;
absorbing radiofrequency (RF) energy by the dosimeter at the resonant frequency of the circuit from an RF transmitter;
determining the resonant frequency of the circuit based on the absorbed RF energy;
determining the capacitance of the varactor based on the determined resonant frequency; and
determining the amount of radiation based on the capacitance of the varactor.
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Accused Products
Abstract
A system for determining an amount of radiation includes a dosimeter configured to receive the amount of radiation, the dosimeter comprising a circuit having a resonant frequency, such that the resonant frequency of the circuit changes according to the amount of radiation received by the dosimeter, the dosimeter further configured to absorb RF energy at the resonant frequency of the circuit; a radio frequency (RF) transmitter configured to transmit the RF energy at the resonant frequency to the dosimeter; and a receiver configured to determine the resonant frequency of the dosimeter based on the absorbed RF energy, wherein the amount of radiation is determined based on the resonant frequency.
29 Citations
20 Claims
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1. A method for determining an amount of radiation, the method comprising:
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receiving the amount of radiation by a dosimeter, the dosimeter comprising a circuit, the circuit having a resonant frequency that is configured to change according to the amount of radiation received by the dosimeter, wherein the circuit comprises a varactor, the varactor comprising; a silicon substrate; and a dielectric layer located on top of the silicon substrate, wherein the amount of radiation causes a corresponding negative charge to build up in the dielectric layer, and the negative charge in the dielectric layer causes a depletion region to form in the silicon substrate underneath the dielectric layer, and wherein a capacitance of the varactor is reduced in response to the formation of the depletion region; absorbing radiofrequency (RF) energy by the dosimeter at the resonant frequency of the circuit from an RF transmitter; determining the resonant frequency of the circuit based on the absorbed RF energy; determining the capacitance of the varactor based on the determined resonant frequency; and determining the amount of radiation based on the capacitance of the varactor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for determining an amount of radiation, comprising:
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a dosimeter configured to receive the amount of radiation, the dosimeter comprising a circuit having a resonant frequency, such that the resonant frequency of the circuit changes according to the amount of radiation received by the dosimeter, the dosimeter further configured to absorb RF energy at the resonant frequency of the circuit, wherein the circuit comprises a varactor, the varactor comprising; a silicon substrate; and a dielectric layer located on top of the silicon substrate, wherein the amount of radiation causes a corresponding negative charge to build up in the dielectric layer, and the negative charge in the dielectric layer causes a depletion region to form in the silicon substrate underneath the dielectric layer, and wherein a capacitance of the varactor is reduced in response to the formation of the depletion region; a radiofrequency (RF) transmitter configured to transmit the RF energy at the resonant frequency to the dosimeter; and a receiver configured to determine the resonant frequency of the dosimeter based on the absorbed RF energy, wherein the capacitance of the varactor is determined based on the resonant frequency and the amount of radiation is determined based on the capacitance of the varactor. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A device for determining an amount of radiation, comprising:
a circuit, the circuit having a resonant frequency, the circuit comprising; a varactor, the varactor comprising; a silicon substrate; and a dielectric layer located on top of the silicon substrate, wherein the amount of radiation causes a corresponding negative charge to build up in the dielectric layer, and the negative charge in the dielectric layer causes a depletion region to form in the silicon substrate underneath the dielectric layer, and wherein a capacitance of the varactor is reduced in response to the formation of the depletion region, and the resonant frequency changes according to the capacitance; an inductor in series with the varactor; and an antenna in series with the varactor and the inductor that is configured to absorb radiofrequency (RF) energy at the resonant frequency, such that the amount of radiation is determined based on the absorbed RF energy. - View Dependent Claims (19, 20)
Specification