US Patent No. 10,143,045

RADIO FREQUENCY HEATING APPARATUS


Patent No. 10,143,045
Issue Date November 27, 2018
Title Radio Frequency Heating Apparatus
Inventorship Robin Wesson, Nijmegen (NL)
Roger Williams, Barrington, RI (US)
Assignee Ampleon Netherlands, B.V., Nijmegen (NL)

Claim of US Patent No. 10,143,045

1. An radio frequency (RF) heating apparatus comprising:a cavity for receiving an object to be heated;
an oscillator for generating a common phase reference signal;
a plurality of channels for generating RF radiation to be introduced into the cavity, wherein each channel comprises:
an RF frequency synthesiser;
a coherent quadrature modulator for modulating a first RF signal outputted by the RF frequency synthesiser;
a controller for outputting control signals to the modulator for controlling at least one of phase and amplitude of the modulated first RF signal;
a power amplifier for amplifying the modulated first RF signal;
an antenna connected to an output of the power amplifier;
a forward signal detection coherent quadrature demodulator;
a reverse signal detection coherent quadrature demodulator; and
a directional coupler connected in between the power amplifier and the antenna, the directional coupler being connected to the forward signal detection coherent quadrature demodulator and to the reverse signal detection coherent quadrature demodulator by a forward signal coupled path and a reverse signal coupled path, respectively,
wherein the forward signal detection coherent quadrature demodulator is configured to monitor an RF signal that is introduced in the cavity by the antenna and wherein the reverse signal detection coherent quadrature demodulator is configured to monitor an RF signal that is reflected back from the cavity,
wherein the forward signal detection and the reverse signal detection coherent quadrature demodulators are configured to provide their respective output to the controller,
wherein the controller is configured to use the output from the forward signal detection and the reverse signal detection coherent quadrature demodulators to alter operation of the channel for modifying the RF radiation that is introduced to the cavity, and
wherein the common phase reference signal is used to synchronise the frequency synthesisers of each channel in terms of at least one of frequency and phase.