US Patent No. 10,602,573

ESTABLISHING RF EXCITATION SIGNAL PARAMETERS IN A SOLID-STATE HEATING APPARATUS


Patent No. 10,602,573
Issue Date March 24, 2020
Title Establishing Rf Excitation Signal Parameters In A Solid-state Heating Apparatus
Inventorship Minyang Ma, Tempe, AZ (US)
Gregory J. Durnan, Tempe, AZ (US)
Steven Y. Do, Chandler, AZ (US)
Assignee NXP USA, Inc., Austin, TX (US)

Claim of US Patent No. 10,602,573

1. A method of establishing parameter values for radio frequency (RF) excitation signal parameters in a solid-state heating apparatus that includes an oven that has a cavity configured to contain a load that includes an object to be heated, and the method comprises:determining at least one characteristic of the load in the cavity;
producing a plurality of stored reflected power indications by performing multiple iterations of a process that includes, for each iteration of the multiple iterations:
setting a plurality of the RF excitation signal parameters to a unique combination of parameter values that is different from combinations of parameter values used in other iterations of the multiple iterations, wherein the plurality of RF excitation signal parameters includes at least one excitation signal frequency and at least one phase shift,
providing, by the solid-state heating apparatus, a plurality of RF excitation signals to a plurality of microwave energy radiators that are proximate to the cavity, wherein the plurality of RF excitation signals have signal characteristics that are defined according to the unique combination of parameter values,
while the plurality of RF excitation signals are being provided, generating a measured reflected RF power value by measuring, by at least one power detection circuit of the solid-state heating apparatus, reflected RF power that indicates a magnitude of RF power that is reflected from the cavity,
determining, based on the measured reflected RF power value, a reflected power indication, and
storing the reflected power indication to produce a stored reflected power indication corresponding to the unique combination of parameter values;
identifying a particular one of the plurality of stored reflected power indications that indicates a lowest reflected power or return loss in comparison with the reflected power or return loss indicated by previously of the plurality of stored reflected power indications, or that indicates a reflected power or return loss that falls below a pre-determined threshold;
designating the unique combination of parameter values corresponding to the particular one of the plurality of stored reflected power indications as an acceptable combination of RF signal parameter values; and
storing, in a memory of the heating apparatus, the acceptable combination of RF signal parameter values in a table that correlates the acceptable combination of the RF signal parameter values with the at least one characteristic of the load.