IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0579381
(2009-10-14)
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등록번호 |
US-8774743
(2014-07-08)
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발명자
/ 주소 |
- Ali, Shirook
- Warden, James Paul
- Bakr, Mohamed
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출원인 / 주소 |
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대리인 / 주소 |
Novak Druce Connolly Bove + Quigg LLP
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인용정보 |
피인용 횟수 :
25 인용 특허 :
26 |
초록
▼
Real-time calibration of a tunable matching network that matches the dynamic impedance of an antenna in a radio frequency receiver system. The radio frequency receiver system includes two non-linear equations that may be solved to determine the reflection coefficient of the antenna. The tunable matc
Real-time calibration of a tunable matching network that matches the dynamic impedance of an antenna in a radio frequency receiver system. The radio frequency receiver system includes two non-linear equations that may be solved to determine the reflection coefficient of the antenna. The tunable matching network is repeatedly perturbed and the power received by the antenna is measured after each perturbation at the same node in the matching network. The measured power values are used by an optimizer in converging to a solution that provides the reflection coefficient of the antenna. The reflection coefficient of the antenna may be used to determine the input impedance of the antenna. The elements of the matching circuit are then adjusted to match the input impedance of the antenna.
대표청구항
▼
1. A wireless communications system, comprising: a tunable matching network having an input and an output, the output of the tunable matching network connected via a low noise amplifier to an input of a power detector, an output of the power detector connected to a radio frequency receiver in a rece
1. A wireless communications system, comprising: a tunable matching network having an input and an output, the output of the tunable matching network connected via a low noise amplifier to an input of a power detector, an output of the power detector connected to a radio frequency receiver in a receiver system;an antenna connected at the antenna feedpoint to the input of the tunable matching network to input electromagnetic signals from the antenna to the radio frequency receiver;a control system configured to use three different measurements of power levels detected at a single location by the power detector to calculate, in real-time, a complex value of an input impedance of the antenna at the antenna feedpoint, by using the three different power measurements simultaneously to solve two non-linear equations, and to tune the matching network to match its input impedance to the calculated value of the input impedance of the antenna. 2. The wireless communications system of claim 1, wherein the control system comprises: computer executable program code for calculating the complex values of the input impedance;a controller configured to execute the computer executable program code that calculates values of the input impedance; anda non-linear optimizer for said solving of said two non-linear equations by convergence, wherein the convergence to an actual value of the input impedance of the antenna is at a quadratic rate of convergence. 3. The wireless communications system of claim 2, wherein the non-linear optimizer of the receiver system receives a reference received power value, a first received power value, and a second received power value to determine a reflection coefficient of the antenna. 4. The wireless communications system of claim 3, wherein the reference received power value, first received power value, and second received power value are represent measurements at the same specific node after the low noise amplifier. 5. The wireless communications system of claim 3, wherein the first received power value is the power measured of the receiver system after a first perturbation of a number of reactive elements in the matching network. 6. The wireless communications system of claim 3, wherein the second received power value is the power measured from the receiver system after a second perturbation of a number of reactive elements in the matching network, wherein the first perturbation is different from the second perturbation. 7. The wireless communications system of claim 3, wherein the controller converts the determined reflection coefficient of the antenna to the input impedance of the antenna. 8. The wireless communications system of claim 7, further comprising: a digital-to-analog converter that converts the input impedance of the antenna to a number of voltage values that tune the matching network. 9. The wireless communications system of claim 3, comprising: computer executable program code that calculates, in real-time, values that match the input impedance of the antenna;computer executable program code that inputs the reference received power value;computer executable program code that inputs the first received power value measured after a first perturbation of the wireless system;computer executable program code that inputs the second received power value measured after a second perturbation of the wireless system; andcomputer executable program code that determines the value of an input impedance of an antenna of the wireless system through convergence of the non-linear optimizer. 10. The wireless communications system of claim 1, further comprising: a digital-to-analog converter that converts the calculated value of the input impedance to a tuning parameter of the matching network. 11. The wireless communications system of claim 10, wherein the matching network comprises reactive elements that are variable and tunable by the tuning parameter. 12. The wireless communications system of claim 1, a first non-linear equation of the two non-linear equations is formulated as: PL(1)PL(0)=S22(1)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(1)ΓL21-ΓAΓin(1)2, wherein PL(1)PL(0) is the ratio of power received by the load and measured after the low noise amplifier at a first tuning position of the reactive elements of the matching network; S22(1) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a first perturbation of the matching network; S22(o) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; ΓL is a reflection coefficient of the load, and Γ□in(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γ□in(1) is an input reflection coefficient of the matching network as seen from the antenna after a first perturbation of the matching network; and ΓA is the reflection coefficient of the antenna. 13. The wireless communications system of claim 1, wherein a second non-linear equation of the two non-linear equations is formulated as: PL(2)PL(0)=S21(2)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(2)ΓL21-ΓAΓin(2)2, wherein PL2PL(0) is the ratio of power received by the load and measured after the low noise amplifier at a second tuning position of the reactive elements of the matching network; S22(2) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a second perturbation of the matching network; S22(0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; S21(2) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output after a second perturbation of the matching network; ΓL is a reflection coefficient of the load, and Γ□in(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γ□in(2) is an input reflection coefficient of the matching network as seen from the antenna after a second perturbation of the matching network; and ΓA is the reflection coefficient of the antenna. 14. A network server comprising a computer recordable storage medium tangibly embodying computer executable program code, which when executed by a controller, performs actions comprising: solving, with a non-linear optimizer, for a reflection coefficient of an antenna in a receiver by calculating a solution to two non-linear equations_herein the calculation uses three different power measurements simultaneously, where the three different power measurements of power level were detected at a single location by a power detector;converting, through the controller, the reflection coefficient to a value of an input impedance of the antenna; andtuning a number of reactive elements of a matching network to values that match the input impedance wherein the reactive elements are a tunable matching network having an input and an output, the output of the tunable matching network connected via a low noise amplifier to an input of a power detector, an output of the power detector connected to the receiver. 15. The network server of claim 14, wherein a first non-linear equation of the two non-linear equations is formulated as: PL(1)PL(0)=S22(1)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(1)ΓL21-ΓAΓin(1)2, wherein PL(1)PL(0) is the ratio of power received after the low noise amplifier at a first tuning position of the reactive elements of the matching network; S22(1) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a first perturbation of the matching network; S22(0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; ΓL is a reflection coefficient of the load, and Γin(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γin(1) is an input reflection coefficient of the matching network as seen from the antenna after a first perturbation of the matching network; and ΓA is the reflection coefficient of the antenna. 16. The network server of claim 14, wherein a second non-linear equation of the two non-linear equations is formulated as: PL(2)PL(0)=S21(2)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(2)ΓL21-ΓAΓin(2)2, wherein PL(2)PL(0) is the ratio of power received after the low noise amplifier at a second tuning position of the reactive elements of the matching network; S22(2) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a second perturbation of the matching network; S22(0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; S21(2) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output after a second perturbation of the matching network; ΓL is a reflection coefficient of the load, and Γin(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γin(2) is an input reflection coefficient of the matching network as seen from the antenna after a second perturbation of the matching network; and ΓA is the reflection coefficient of the antenna. 17. A computer implemented method of matching the impedance of an antenna in a receiver, the computer implemented method comprising: solving with a non-linear optimizer, for a reflection coefficient of an antenna, ΓA, by calculating simultaneously a solution to two non-linear equations, wherein the calculation uses three different power measurements, where the three different power measurements of power level were detected at a single location by a power detector;converting, through a controller, the reflection coefficient to a complex value of an input impedance of the antenna; andtuning a number of reactive elements of a matching network to values that match the input impedance wherein the reactive elements are a tunable matching network having an input and an output, the output of the tunable matching network connected via a low noise amplifier to an input of a power detector, an output of the power detector connected to the receiver. 18. The computer implemented method of claim 17, wherein each non-linear equation of the two non-linear equations are expressed as the ratios of two powers measured by a control system of the wireless communication system. 19. The computer implemented method of claim 18, wherein a first non-linear equation is formulated as: PL(1)PL(0)=S22(1)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(1)ΓL21-ΓAΓin(1)2, wherein PL(1)PL(0) is the ratio of power received after the low noise amplifier at a first tuning position of the reactive elements of the matching network; S22(1) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a first perturbation of the matching network; S22(0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; ΓL is a reflection coefficient of the load, and Γin(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γin(1) is an input reflection coefficient of the matching network as seen from the antenna after a first perturbation of the matching network; and ΓA is the reflection coefficient of the antenna. 20. The computer implemented method of claim 18, wherein a second non-linear equation is formulated as: PL(2)PL(0)=S21(2)21-S22(0)ΓL21-ΓAΓin(0)2S21(0)21-S22(2)ΓL21-ΓAΓin(2)2, wherein PL(2)PL(0) is the ratio of power received after the low noise amplifier at a second tuning position of the reactive elements of the matching network; S22(0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S22(2) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a second perturbation of the matching network; S21(0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; S21(2) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output after a second perturbation of the matching network; ΓL is a reflection coefficient of the load, Γin(0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γin(2) is an input reflection coefficient of the matching network as seen from the antenna after a second perturbation of the matching network; and ΓA is the reflection coefficient of the antenna.
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