Adaptively tunable antennas incorporating an external probe to monitor radiated power
View Patent ↗An embodiment of the present invention an apparatus, comprising an apparatus, comprising an adaptively-tuned antenna including a variable reactance network connected to the antenna, an RF field probe located near the antenna, an RF detector to sense voltage from the field probe, a controller that monitors the RF voltage and supplies control signals to a driver circuit and wherein the driver circuit converts the control signals to bias signals for the variable reactance network.
1. A method comprising:
obtaining an RF voltage present on an RF field probe that is located in proximity to an antenna of a communication device, wherein the RF voltage is generated based on radiated power of the antenna, and wherein the RF voltage is sensed by an RF detector of the communication device;
utilizing a processor for generating control signals based on the obtained RF voltage; and
providing the control signals to a driver circuit for conversion into bias voltages that are used by a variable reactance network of the communication device for tuning the antenna via applying the bias voltages to at least one variable capacitor of the variable reactance network to adjust a capacitance of the at least one variable capacitor.
2. The method of claim 1 , wherein the processor is a digital processor, and wherein the providing of the control signals and the conversion into the bias voltages is an iterative process.
3. The method of claim 1 , wherein the RF probe is positioned within one Wheeler radian sphere of a center of the antenna.
4. The method of claim 1 , wherein the variable reactance network comprises at least one of a semiconductor varactor, a micro-electro-mechanical systems (MEMS) varactor, a MEMS switched reactive element, a semiconductor switched reactive element or a ferroelectric capacitor.
5. The method of claim 1 , wherein the antenna comprises a patch antenna, a monopole antenna or a slot antenna.
6. The method of claim 1 , wherein the capacitance of the at least one variable capacitor is adjusted differently for transmit and receive modes of the communication device.
7. The method of claim 1 , wherein the adjusting of the capacitance of the at least one variable capacitor causes the RF voltage to increase.
8. The method of claim 1 , wherein the antenna comprises a planar inverted F antenna.
9. A method comprising:
obtaining an RF voltage present on an RF field probe that is located in proximity to an antenna of a communication device, wherein the RF voltage is generated based on radiated power of the antenna, and wherein the RF voltage is sensed by art RF detector of the communication device;
generating, by a processor, control signals in an iterative process based on the obtained RF voltage; and
providing the control signals to a driver circuit for conversion into bias voltages that are used by a variable reactance network of the communication device for tuning the antenna via applying the bias voltages to at least one variable capacitor of the variable reactance network to adjust a capacitance of the at least one variable capacitor.
10. The method of claim 9 , wherein the antenna comprises a planar inverted F antenna.
11. The method of claim 9 , wherein the RF probe is positioned within one Wheeler radian sphere of a center of the antenna.
12. The method of claim 9 , wherein the antenna comprises a patch antenna.
13. The method of claim 9 , wherein the antenna comprises a monopole antenna.
14. The method of claim 9 , wherein the at least one variable capacitor comprises a voltage tunable ferroelectric variable capacitor, and wherein a capacitance of the voltage tunable ferroelectric variable capacitor is adjusted differently for transmit and receive modes of the communication device.
15. The method of claim 9 , wherein the antenna comprises a slot antenna.
16. A method comprising:
obtaining an RF voltage present on an RF field probe that is located in proximity to an antenna of a communication device, wherein the RF voltage is generated based on radiated power of the antenna, and wherein the RF voltage is sensed by an RF detector of the communication device;
generating, by a processor, control signals based on the obtained RF voltage; and
providing the control signals to a driver circuit for conversion into bias voltages that are used by a variable reactance network of the communication device for tuning the antenna via applying the bias voltages to at least one variable capacitor of the variable reactance network to adjust a capacitance of the at least one variable capacitor wherein the capacitance of the at least one variable capacitor is adjusted differently for transmit and receive modes of the communication device.
17. The method of claim 16 , wherein the at least one variable capacitor comprises a voltage tunable ferroelectric variable capacitor, and wherein the adjusting of the capacitance of the at least one variable capacitor causes the RF voltage to increase.
18. The method of claim 16 , wherein the antenna comprises a planar inverted F antenna.
19. The method of claim 16 , wherein the variable capacitor comprises a MEMS switched variable capacitor.
20. The method of claim 16 , wherein the variable capacitor comprises a semiconductor switched variable capacitor.