Radio frequency device with compensation of permittivity dispersion of the substrate and adjustment method

Patent metadata

Field	Value
Publication number	US-9985602-B2
Application number	US-201314097200-A
Country	US
Kind code	B2
Filing date	Dec 4, 2013
Priority date	Dec 5, 2012
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

The invention relates to a device for transmitting and/or receiving radio frequency signals comprising at least one antenna and/or at least one filter realised in printed technology on a dielectric substrate. According to the invention, this device is equipped with means for compensating the permittivity dispersions of the substrate. For this purpose, the device comprises a circuit for measuring the dielectric permittivity of the substrate able to deliver a measured permittivity value and adjustment means able to adjust the impedance of the antenna and/or the frequency response of said filter according to said measured permittivity value.

First claim

The invention claimed is:

1. A device for processing radio frequency signals comprising:
at least one antenna;
at least one filter, said at least one antenna and said at least one filter being provided on a dielectric substrate;
a circuit, configured to measure a value linked to a dielectric permittivity of the dielectric substrate on which said at least one antenna and said at least one filter are provided and
to adjust at least one of an impedance of the at least one antenna and a frequency response of said at least one filter according to said measured value linked to said dielectric permittivity of the dielectric substrate on which said at least one antenna and said at least one filter are provided.

2. The device according to claim 1 , wherein the circuit receives the measured value linked to the dielectric permittivity and generates at least one digital control signal according to said measured value; and the device further comprises at least one of an impedance matching network connected to an input/output of said at least one antenna and controlled by said at least one digital control signal to modify the impedance of the at least one antenna and restore the impedance to a predetermined value and a variable-capacitance element, in said at least one filter, controlled by said at least one digital control signal to modify the frequency response of said at least one filter and restore the frequency response to a predetermined value.

3. The device according to claim 2 , wherein the impedance matching network comprises an adjustable capacitor digitally controlled by said at least one digital control signal.

4. The device according to claim 2 , wherein the variable-capacitance element in said at least one filter is a varactor diode.

5. The device according to claim 1 , wherein the measuring circuit comprises:
a radio frequency signal generator digitally controlled by a control signal to generate a plurality of radio frequency signals of different frequencies within a predetermined frequency band;
a resonator, configured to receive the radio frequency signals generated by the radio frequency signal generator and to deliver, for each of these signals of different frequencies, an output signal;
a power measuring circuit, configured to measure the signal power for each of the output signals delivered by said resonator;
a microcontroller, configured to determine the resonance frequency of the resonator from the signal power measured by the power measuring circuit and to generate the control signal for controlling the radio frequency signal generator; and
a processor, configured to calculate a relative dielectric permittivity of the substrate from said determined resonance frequency.

6. The device according to claim 5 , wherein said resonator is a ring resonator.

7. The device according to claim 5 , wherein the resonator has a resonance frequency close to the frequency of the radio frequency signals.

8. The device according to claim 5 , further comprising at least two channels operating at different operating frequencies each of the at least two channels comprising
at least one antenna;
at least one filter, said at least one antenna and said at least one filter being provided on a single dielectric substrate;
the circuit configured to measure a value linked to the dielectric permittivity for measuring a relative dielectric permittivity of said dielectric substrate on which said at least one antenna and said at least one filter are provided, wherein the resonator of the circuit measuring a value linked to the dielectric permittivity is designed to have a resonance frequency close to the highest operating frequency.

9. A method for adjusting at least one of an impedance of an antenna and a frequency response of a filter of a device, comprising:
generating a plurality of radio frequency signals of different frequencies in a predetermined frequency band;
measuring a relative permittivity value of a dielectric substrate on which the antenna and filter are provided; and
delivering control signals for adjusting at least one of the impedance of the antenna and the frequency response of the filter according to said measured relative permittivity value of the dielectric substrate on which said at least one antenna and said at least one filter are provided.

10. The method according to claim 9 , wherein the method is performed when the device is first switched on.

11. The method according to claim 9 , further comprising:
receiving the measured relative permittivity value;
generating at least one digital control signal according to said measured relative permittivity value; and, at least one of:
modifying, by an impedance matching network, the impedance of the antenna to restore the impedance to a predetermined value; and
modifying, by a variable-capacitance element, the frequency response of the filter to restore the frequency response to a predetermined value.

12. The method according to claim 9 , wherein the impedance matching network comprises an adjustable capacitor digitally controlled by said at least one digital control signal.

13. The method according to claim 11 , wherein the variable-capacitance element is a varactor diode.

14. The method according to claim 9 , wherein the measuring comprises:
generating, by a radio frequency signal generator, a plurality of radio frequency signals of different frequencies inside a predetermined frequency band;
receiving, by a resonator, the radio frequency signals generated by the radio frequency signal generator and delivering, for each of these signals of different frequencies, an output signal;
measuring, by a power measuring circuit, the signal power for each of the output signals delivered by said resonator;
determining, by a microcontroller, the resonance frequency of the resonator from the power values measured by the power measuring circuit and generating the control signal for controlling the radio frequency signal generator; and
calculating, by a processor, the relative permittivity of the substrate from said determined resonance frequency.

15. The method according to claim 14 , wherein said resonator is a ring resonator.

16. The method according to claim 14 , wherein the resonator has a resonance frequency close to the frequency of the radio frequency signals.

17. The method according to claim 14 , wherein the device includes at least two channels operating at different operating frequencies, each of the at least two channels:
measuring, by a measuring circuit, a value linked to the permittivity for measuring the relative permittivity of said dielectric substrate, wherein a resonator of the measuring circuit is designed to have a resonance frequency close to the highest operating frequency.

Assignees

• Thomson Licensing

Inventors

• Robert Jean-Luc
• Lo Hine Tong Dominique
• Minard Philippe

Classifications

• H01Q9/065 Primary

  Microstrip dipole antennas (patch antenna H01Q9/0407) · CPC title

• H03H7/40 Primary

  Automatic matching of load impedance to source impedance · CPC title

• H04L65/00

  Network arrangements, protocols or services for supporting real-time applications in data packet communication (real-time or near real-time messaging, e.g. instant messaging [IM] H04L51/04; selective video distribution H04N21/00) · CPC title

• H03H11/28 Primary

  Impedance matching networks · CPC title