Patent Description:
The processing of poultry may include activities such as sexing to determine gender, inoculating, or otherwise medicating the birds, feeding the birds, weighing the birds, and processing the beaks and/or claws of the birds, for example, to retard their growth, among other activities.

In recent years, some systems have delivered energy to selected poultry tissue for purposes of processing. <CIT>; <CIT>; <CIT>; and <CIT> describe some systems and methods for processing beaks and claws of poultry that are more welfare friendly methods to the bird. <CIT> shows with an electrosurgical coagulator, <CIT> discloses a device for radiating the human skin, and <CIT> shows a microwave ablation device for medical use. <CIT>, on the other hand, discloses poultry treatment configured for applying microwave, ultrasound, or electrical energy to remove poultry claws from live poultry toes. There remains a need for improved energy delivery systems that even more precisely deliver energy.

The system and a method according to the invention are defined by claim <NUM> and claim <NUM> respectively. Various aspects of the present disclosure relate to a system that uses an electric field to process animal tissue. The design of the system includes an attenuator operably coupled between a radio frequency (RF) synthesizer and at least one amplifier to provide a precise and dynamic power gain control of an RF electric signal over a wide range, for example, up to <NUM> dB to generate an alternating RF electric field. In particular, the attenuator may be adjusted without adjusting some or all amplifiers. The system may selectively provide a low- or high-power alternating RF electric field. The system may have an RF interface board designed to isolate sensing circuitry from high-power signals. The system may be used in various applications, such as the processing of poultry claws, beaks/bills, etc. Processing may be accomplished using one or more non-contact energy sources, such as an electric field. Processing may include delivery of energy to selected tissue in amounts sufficient to retard, or slow, future growth but not directly remove the tissue. Processing may also include delivery of energy to selected tissue in amounts sufficient to remove the tissue.

In one aspect, an energy delivery system comprises an RF synthesizer circuit configured to generate an RF electric signal. The system also comprises a preamplification stage operably coupled to an output of the RF synthesizer circuit. The preamplification stage comprises an attenuator. The system also comprises a board controller operably coupled to the attenuator of the preamplification stage. The board controller is configured to modify a gain setting of the attenuator. The system further comprises an output connection configured to provide a low-power signal or a high-power signal based on at least the RF electric signal and the gain setting of the attenuator. The low-power signal or the high-power signal is configured to be provided to an RF applicator configured to couple an alternating RF electric field to animal tissue.

In another aspect, a method of delivering energy to animal tissue comprises synthesizing an RF electric signal; adjusting attenuation of the RF electric signal to selectively provide a low-power signal or a high-power signal; and generating an alternating RF electric field from an RF applicator based on the low-power signal or the high-power signal to couple the alternating RF electric field to animal tissue.

Various embodiments of the present disclosure are described in detail herein with respect to the following drawings:.

This disclosure relates to energy delivery systems and, in particular, to energy delivery systems that use one or more non-contact energy sources, such as electric fields, that couple to animal tissue. Although reference is made herein to poultry systems, such as a poultry claw system used to deliver energy to each claw in amounts sufficient to retard claw growth but not directly remove the claw, the energy delivery systems may be used with any poultry, or other animal, tissue, for which processing may be desirable (e.g., beak/bill tissue of poultry, etc.). The processing concerning the delivery of energy to selected tissue in amounts sufficient to remove tissue is not encompassed in the claimed invention. Various other applications for energy delivery systems will become apparent to one of ordinary skill in the art having the benefit of the present disclosure.

It may be beneficial to provide an energy delivery system having precise and dynamic control over a wide range of power gains to provide alternating radio frequency (RF) electric fields, particularly in tissue processing systems for animals. It may be beneficial to provide an energy delivery system capable of providing a low- or high-power RF electric field to facilitate detecting and processing of animal tissue using the same system. Further, it may be beneficial for the energy delivery system to control the RF electric field precisely to provide targeted energy to the animal tissue to achieve the desired processing while mitigating undesirable effects.

The present disclosure provides a system that uses an electromagnetic field to process animal tissue. The system may be used in poultry processing for stunting the growth of poultry claws. The system may selectively provide a low- or high-power alternating RF electric field. The low-power alternating RF electric field may be used for sensing the presence of animal tissue. The high-power alternating RF electric field may be used for processing the animal tissue. Some commercially-available high-power RF amplifiers are not capable of precise dynamic gain control at low gains. Advantageously, in various embodiments of the present disclosure, one or more preamplification stages may be used to provide precise, dynamic attenuation or amplification over a wide range of power gains. In some embodiments, the preamplification stage paired with one or more amplification stages may provide a wide range of dynamic gain control range, for example, up to <NUM> dB for an RF electric signal that can be used to provide an alternating RF electric field.

In some embodiments, attenuators are adjusted instead of adjusting amplifiers to provide the dynamic gain range. Frequency tracking may be used in conjunction with the high-power alternating RF electric field to improve coupling to animal tissue while processing. Further, in some embodiments, the system may have an RF interface board designed to isolate sensing circuitry to facilitate power sensing when providing either low- or high-power output RF electric signals.

As used herein, the term "animal tissue" refers non-human tissue. Non-limiting examples of animal tissue include a poultry claw, beak/bill, or other appendage.

As used herein, the term "applicator" or "RF applicator" refers to a structure configured to provide an alternating RF electric field in response to receiving an RF electric signal. The applicator is configured to couple alternating RF electric field energy into animal tissue. In contrast to an RF antenna, an RF applicator directs, or concentrates, alternating RF electric field energy locally at a point proximate to, or within a close proximity to, the surface of the structure instead of transmitting the RF electric field to a receiving antenna across a medium.

As used herein, the term "or" is generally employed in its inclusive sense, for example, to mean "and/or" unless the context clearly dictates otherwise. The term "and/or" means one or all the listed elements or a combination of at least two of the listed elements.

Reference will now be made to the drawings, which depict one or more aspects described in this disclosure. However, it will be understood that other aspects not depicted in the drawings fall within the scope of this disclosure. Like numbers used in the figures refer to like components, steps, and the like. However, it will be understood that the use of a reference character to refer to an element in a given figure is not intended to limit the element in another figure labeled with the same reference character. In addition, the use of different reference characters to refer to elements in different figures is not intended to indicate that the differently referenced elements cannot be the same or similar.

<FIG> shows energy delivery system <NUM> according to the present disclosure. System <NUM> includes one or more of components, such as system controller <NUM>, RF interface board <NUM>, and RF applicator <NUM>.

System controller <NUM> may be operably connected to RF interface board <NUM> to provide, or issue, commands and settings to RF interface board <NUM>. RF interface board <NUM> may use a calibration or compensation table to correct for signal drift due to changes in frequency or temperature affecting one or more components of RF interface board <NUM>.

RF interface board <NUM> may be configured to generate an RF electric signal. The RF electric signal may be amplified or attenuated by various components of RF interface board <NUM> to produce an output RF electric signal. In some embodiments, RF interface board <NUM> includes at least an RF synthesizer circuit, an attenuator, an amplifier, a sensing circuit, and an output connection to provide the output RF electric signal. The RF interface board <NUM> is configured to provide a low- or high-power output RF electric signal based the generated RF electric signal. RF interface board <NUM> may include one or more: additional attenuators, additional amplifiers, temperature sensors, and electromagnetic shielding components.

RF applicator <NUM> may be operably connected to RF interface board <NUM> to generate an alternating RF electric field in response to receiving the output RF electric signal. RF applicator <NUM> may be operably connected to the output connection of RF interface board <NUM>. RF applicator <NUM> may be formed of any suitable structure capable of producing, or transmitting, an alternating RF electric field. In some embodiments, RF applicator <NUM> includes a conductive material and a dielectric material. For example, RF applicator <NUM> may include two conductors separated by a dielectric material. Non-limiting examples of the dielectric material include a polymer, such as polytetrafluoroethylene (PTFE), such as TEFLON™, or a free-space dielectric (air).

RF interface board <NUM> is configured to carry out, or execute, one or more commands provided by system controller <NUM>. In some embodiments, RF interface board <NUM> is configured to receive commands including one or more of: a constant power output command, a detection mode command, a high-power tracking mode command, an error reporting command, a temperature sensing command, a shutdown command, and a turn on command.

Various commands may be used during operation of the energy delivery system. In response to the constant power output command, RF interface board <NUM> may provide a constant power RF electric signal to the output connection. For example, the constant power may correspond to a low- or high-power output RF electric signal. In response to the detection mode, RF interface board <NUM> may be configured to detect a change in return loss of the low-power signal. Further, RF interface board <NUM> may notify system controller <NUM> when the reflected power drops below, or return loss rises above, a threshold value. The detection mode may be used in conjunction with providing the low-power output RF electric signal to RF applicator <NUM>. When detected return loss rises, animal tissue may be positioned in close proximity to RF applicator <NUM>, and system controller <NUM> may command RF interface board <NUM> to provide a high-power output RF electric signal. In response to the high-power tracking mode, RF interface board <NUM> may modify the frequency of the generated RF electric signal to reduce, or minimize, the reflected power or increase, or maximize, the return loss detected by RF interface board <NUM>, which may improve coupling of RF energy to animal tissue. In other words, frequency may be adjusted to match the electrical load detected. The high-power tracking mode may be used in conjunction with providing the high-power output RF electric signal to increase, or maximize, the coupling of alternating RF electric field energy to animal tissue at the beginning of processing and throughout processing (e.g., impedance may change as animal tissue is processed).

Various frequencies may be used to drive RF applicator <NUM> for delivering energy to animal tissue. In some embodiments, the RF interface board <NUM> may be configured to provide an RF electric signal corresponding to frequencies in one or more industrial, scientific, or medical (ISM) frequency bands, which may be reserved in one or more countries for the use of RF energy intended for scientific, medical, and industrial uses rather than for communications. In one or more embodiments, the RF electric signal includes at least one frequency in the ISM frequency band from <NUM> to <NUM> and may be centered, or have a peak, at <NUM>.

RF applicator <NUM> may be coupled to a receptacle that defines a processing position for animal tissue. The receptacle is configured to guide animal tissue to the processing position proximate to RF applicator <NUM>, in which the alternating RF electric field will couple to the animal tissue. In some embodiments, such as for poultry claw processing systems, the receptacle may be described as a claw guide.

2A shows a first side view of one example of RF applicators <NUM> coupled to receptacle <NUM>. As illustrated, three RF applicators <NUM> are coupled to receptacle <NUM>. Each RF applicator <NUM> may include one input connection <NUM> configured to couple to the output connection of RF interface board <NUM>. Each RF applicator <NUM> may be driven independently, for example, by a different RF interface board <NUM>. In some embodiments, input connections <NUM> may include coaxial connectors.

Receptacle <NUM> may include one or more channels <NUM> configured to guide animal tissue into proximity to RF applicators <NUM>. In the illustrated embodiment, channels <NUM> complement the shape and size of a poultry foot and position the distal end of each poultry claw proximate to one RF applicator <NUM>. For processing chickens, for example, channels <NUM> may have a shape that includes three front-claw channels extending from a rear-claw channel. Each poultry claw may be processed independently, at different times or concurrently.

2B shows one example of RF applicator <NUM> positioned adjacent to animal tissue <NUM>. In some embodiments, at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or even <NUM> percent of the RF electric field energy (of total radiated power) is directed to a volume within <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> centimeters from the surface of the structure. In one or more embodiments, at least <NUM>% or at least <NUM>% of total radiated power is directed within 10x of distance <NUM> from RF applicator <NUM> to ground plane <NUM> based on a finite element model, such as COMSOL for electromagnetic field modeling, of RF applicator <NUM>. For example, a SolidWorks CAD model of the product may be provided to the finite element model along with dielectric properties, such as relative permittivity and loss factor (or loss tangent), and the total radiated power pattern may be calculated. In some embodiments, distance <NUM> between RF applicator <NUM> and ground plane <NUM> is about <NUM> (about <NUM> inches).

<FIG> shows one example of a layout for RF interface board <NUM> according to one embodiment of the present disclosure. RF interface board <NUM> may include one or more of: board controller <NUM>, RF synthesizer circuit <NUM>, one or more attenuator stages <NUM>, one or more additional stages <NUM>, forward sensing circuit <NUM>, circulator <NUM>, output connection <NUM>, and reverse sensing circuit <NUM>. Each component of RF interface board <NUM> may be coupled to, or disposed on, a single substrate. The substrate may be a printed circuit board.

Board controller <NUM> may be operably connected to system controller <NUM> to receive commands or settings. Board controller <NUM> may also provide data to system controller <NUM>, such as a return loss value. In some embodiments, board controller <NUM> includes a communications interface, or connection, coupled wirelessly or by wire to system controller <NUM>. In some embodiments, board controller <NUM> is operably connected to system controller <NUM> over a controller area network (CAN) bus.

Board controller <NUM> may be operably connected to RF synthesizer circuit <NUM> to provide an RF generation signal, one or more attenuator stages <NUM> to provide gain settings, one or more additional stages <NUM> to provide gain settings, forward sensing circuit <NUM> to detect a forward power value, and reverse sensing circuit <NUM> to detect a reflected power value.

As used herein, the term "gain setting" refers to a gain value or gain parameter and may correspond to gains that attenuate (e.g., negative dB) or amplify (e.g., positive dB). For example, a higher magnitude gain setting may further attenuate or amplify a signal depending on whether the gain setting is positive or negative.

RF synthesizer circuit <NUM> is configured to generate an RF electric signal in response to the RF generation signal. RF synthesizer circuit <NUM> may be configured to generate RF electric signal at one or more frequencies. For example, RF synthesizer circuit <NUM> may generate an RF electric signal containing frequencies in one or more ISM frequency bands.

One or more attenuator stages <NUM> may be operably connected to an output of RF synthesizer circuit <NUM>. At least one attenuator stage <NUM> is configured to provide an intermediate RF electric signal based on the generated RF electric signal. Each attenuator stage <NUM> includes an attenuator and optionally an amplifier. The generated RF electric signal may be attenuated or amplified by one or more attenuator stages <NUM> to provide the intermediate RF electric signal. Each attenuator stage <NUM> may be described as a preamplification stage.

One or more additional stages <NUM> may be operably connected to an output of attenuator stages <NUM>. Additional stages <NUM> are configured to provide an output RF electric signal based on the intermediate RF electric signal. In some embodiments, the intermediate RF electric signal is amplified by one or more additional stages <NUM> to provide the output RF electric signal. Additional stages <NUM> may be more specifically described as driving stages or amplification stages.

Forward sensing circuit <NUM> may be operably connected to an output of additional stages <NUM>. Forward sensing circuit <NUM> is configured to provide a forward power value based on a measurement of the output RF electric signal. Forward sensing circuit <NUM> may include a power detector, which may be electromagnetically isolated, or shielded, from other parts of RF interface board <NUM>. Forward sensing circuit <NUM> may include an output to provide the forward power value to board controller <NUM> and may include a through port to provide the output RF electric signal.

Circulator <NUM> may be operably connected to the through port of forward sensing circuit <NUM> to receive the output RF electric signal. Circulator <NUM> may include multiple ports A, B, C that continuously provide a signal received at each port to a subsequent port in a circular manner. Each port is configured to concurrently receive and provide different signals. For example, a signal received at port A is provided to port B, a signal received at port B is provided to port C, and a signal received at port C is provided to port A.

In the illustrated embodiment, port A of circulator <NUM> is operably connected to the through port of forward sensing circuit <NUM> to receive the output RF electric signal. Circulator <NUM> provides the output RF electric signal to port B. RF applicator <NUM> may be operably connected to port B of circulator <NUM> to receive the output RF electric signal. RF applicator <NUM> may provide an alternating RF electric field in response to the output RF electric signal. Some energy or power of output RF electric signal may be reflected by RF applicator <NUM> back to port B of circulator <NUM>. Any portion of output RF electric signal reflected by RF applicator <NUM> to port B may be provided by circulator <NUM> to port C.

Reverse sensing circuit may be operably connected to port C of circulator <NUM>. Reverse sensing circuit <NUM> is configured to provide a reflected power value based on a measurement of the reflected portion of the output RF electric signal. Reverse sensing circuit <NUM> may include a power detector, which may be electromagnetically isolated, or shielded, from other parts of RF interface board <NUM>. Reverse sensing circuit <NUM> may include an output to provide the reflected power value to board controller <NUM> and may include a through port, for example, to provide energy from the reflected RF electric signal to electrical ground through an impedance element.

RF applicator <NUM> may be configured to be sensitive to the presence of animal tissue in proximity to RF applicator <NUM>. In some embodiments, RF interface board <NUM> may be calibrated to not match impedance with air but, rather, match impedance with animal tissue positioned proximate, or adjacent, to RF applicator <NUM> in the processing position. Impedance matching RF interface board <NUM> with animal tissue may increase, or provide a maximum amount of, energy delivered to animal tissue. In other words, the reflected portion of output RF electric signal is greater when no animal tissue is in the processing position compared to when animal tissue is in the processing position.

As used herein, the term "impedance match" refers to designing an input impedance of an electrical load (e.g., animal tissue) or the output impedance of a corresponding signal source (e.g., RF interface board) to substantially maximize or optimize the power transfer or minimize signal reflection from the electrical load. For example, in some embodiments, the system including the RF interface board may change RF electric signal frequency in order to impedance match the output impedance of the RF interface board with the input impedance of the animal tissue, which may substantially maximize power transfer to the animal tissue, within the constraints of the RF interface board and the system.

Board controller <NUM> may receive both the forward and reflected power values. Board controller <NUM> may be configured to determine a return loss based on the forward and reflected power values (e.g., forward power value minus reflected power value). The return loss may be greater when animal tissue is in the processing position compared to when animal tissue is not in the processing position.

The return loss may be communicated to system controller <NUM>. Based on the return loss, system controller <NUM> may issue different commands to board controller <NUM>. For example, when return loss rises above a return loss threshold value (or reflected power drops or falls below a reflected power threshold value), system controller <NUM> may issue one or more commands to board controller <NUM> to provide a high-power RF output electric signal and to enter the high-power tracking mode. In some embodiments, board controller <NUM> may also be configured to enter into a non-high-power tracking mode, such as a low-power tracking mode.

The return loss threshold value may be determined based on a baseline return loss value. For example, the loss threshold value may be at least <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> dBm greater than the baseline return loss.

One or more of the components, such as controllers, synthesizers, interfaces, sensors (e.g., power or temperature), amplifiers, and attenuators, described herein may include a processor, such as a central processing unit (CPU) or microcontroller unit (MCU), computer, logic array, or other device capable of directing data coming into or out of the RF interface board of energy delivery system. The controller may include one or more computing devices having memory, processing, and communication hardware. The controller may include circuitry used to couple various components of the controller together or with other components operably coupled to the controller. The functions of the controller may be performed by hardware and/or as computer instructions on a non-transient computer readable storage medium.

The processor of the controller may include any one or more of a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some examples, the processor may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller or processor herein may be embodied as software, firmware, hardware, or any combination thereof. While described herein as a processor-based system, an alternative controller could utilize other components such as relays and timers to achieve the desired results, either alone or in combination with a microprocessor-based system.

In one or more embodiments, the exemplary systems, methods, and interfaces may be implemented using one or more computer programs using a computing apparatus, which may include one or more processors and/or memory. Program code and/or logic described herein may be applied to input data/information to perform functionality described herein and generate desired output data/information. The output data/information may be applied as an input to one or more other devices and/or methods as described herein or as would be applied in a known fashion. In view of the above, it will be readily apparent that the controller functionality as described herein may be implemented in any manner known to one skilled in the art.

<FIG> shows one example of a layout for various stages of RF interface board <NUM>, which may include one or more of: first preamplification stage <NUM>, second preamplification stage <NUM>, driving stage <NUM>, and amplification stage <NUM>. Each stage may correspond to a circuit including an attenuator, an amplifier, or both. RF interface board <NUM> may include one or more of: first attenuator <NUM>, first amplifier <NUM>, second attenuator <NUM>, second amplifier <NUM>, third amplifier <NUM>, and fourth amplifier <NUM>. Each attenuator may be described as a variable voltage attenuator (VVA).

First preamplification stage <NUM> may be operably connected to an output of RF synthesizer circuit <NUM> to receive generated RF electric signal. First preamplification stage <NUM> may dynamically attenuate or amplify the generated RF electric signal. In some embodiments, first preamplification stage <NUM> may include first attenuator <NUM> and first amplifier <NUM>. First amplifier <NUM> may be operably connected to an output of first attenuator <NUM>. First amplifier <NUM> may amplify a signal attenuated by first attenuator <NUM>.

In some embodiments, first attenuator <NUM> may be operably connected to board controller <NUM> and may be modulated, or adjusted, with a gain setting to dynamically attenuate the generated RF electric signal. First attenuator <NUM> may be configured to attenuate from a low attenuation value to a high attenuation value. In some embodiments, board controller <NUM> may be configured to not adjust the gain setting of first amplifier <NUM> to dynamically attenuate or amplify the generated RF electric signal. First amplifier <NUM> may be configured to amplify at a fixed amplification value.

To provide the dynamic gain range of first preamplification stage <NUM>, the attenuation values of first attenuator <NUM> may encompass the fixed amplification value of first amplifier <NUM>. For example, the dynamic gain range of first attenuator <NUM> may be from a low attenuation value of -<NUM> dB to a high attenuation value of -<NUM> dB, and the fixed amplification value of first amplifier <NUM> may be <NUM> dB. By adjusting the gain setting of first attenuator <NUM> from the low attenuation value to the high attenuation value, the dynamic gain range of the first preamplification stage <NUM> may extend from <NUM> dB to -<NUM> dB.

Second preamplification stage <NUM> may be operably connected to an output of first preamplification stage <NUM>. Second preamplification stage <NUM> may have the same or similar aspects of first preamplification stage <NUM>. Like first preamplification stage <NUM>, second preamplification stage <NUM> may dynamically attenuate or amplify the generated RF electric signal. In some embodiments, second preamplification stage <NUM> may include second attenuator <NUM> and first amplifier <NUM>. Second amplifier <NUM> may be operably connected to an output of second attenuator <NUM>.

Also, in some embodiments, second attenuator <NUM> may be operably connected to board controller <NUM> and may be adjusted with a gain setting to dynamically attenuate or amplify the generated RF electric signal. Second attenuator <NUM> may be configured to attenuation from a low attenuation value to a high attenuation value. The high and low attenuation values may be the same or different than the attenuation values of first attenuator <NUM>. In other words, the attenuation range of second attenuator <NUM> may be the same or different than the attenuation range of first attenuator <NUM>. In some embodiments, board controller <NUM> may be configured to not adjust the gain setting of second amplifier <NUM> to dynamically attenuate or amplify the generated RF electric signal. Second amplifier <NUM> may be configured to amplify at a fixed amplification value, which may be the same or different as the fixed amplification value of first amplifier <NUM>.

To provide the dynamic gain range of first second preamplification stage <NUM>, the attenuation values of second attenuator <NUM> may encompass the fixed amplification value of second amplifier <NUM>. Like first preamplification stage <NUM>, in some embodiments, by adjusting the gain setting of second attenuator <NUM> from the low attenuation value to the high attenuation value, the dynamic gain range of the second preamplification stage <NUM> may extend from <NUM> dB to -<NUM> dB.

Using the example gain ranges described above, the preamplification stages <NUM>, <NUM> together may provide a dynamic gain range from <NUM> dB to -<NUM> dB. In other words, an intermediate RF electric signal provided by the preamplification stages <NUM>, <NUM> together may correspond to a generated RF electric signal dynamically attenuated <NUM> dB (e.g., a gain of -<NUM> dB) or amplified <NUM> dB.

The gain setting for second attenuator <NUM> may be the same or different than the gain setting for first attenuator <NUM>. In some embodiments, board controller <NUM> increases the attenuation value of second attenuator <NUM> before increasing the attenuation value of first attenuator <NUM>, which may improve the noise floor throughout the dynamic gain range of the combined preamplification stages <NUM>, <NUM>.

In some embodiments, only the gain settings of one or more attenuators may be adjusted. In other words, the gain settings of one or more amplifiers may not be adjusted to change the power level of the output RF electric signal. In general, adjusting the gain values of attenuators instead of amplifiers may improve the control of RF interface board <NUM> to provide a precise power level of the output RF electric signal.

Driving stage <NUM> may include third amplifier <NUM> operably connected to an output of second preamplification stage <NUM> to receive the intermediate RF electric signal. Third amplifier <NUM> may have a fixed amplification value. For example, the fixed amplification value of third amplifier <NUM> may be <NUM> dB. The dynamic gain range of the preamplification stages <NUM>, <NUM> in combination with driving stage <NUM> may be <NUM> dB to - <NUM> dB. In some embodiments, third amplifier <NUM> may have a <NUM> W (+<NUM> dBm) maximum output power.

Amplification stage <NUM> may include fourth amplifier <NUM> operably connected to an output of driving stage <NUM> and configured to provide the output RF electric signal in response to receiving the intermediate RF electric signal. Fourth amplifier <NUM> may have a fixed amplification value. For example, the fixed amplification value of fourth amplifier <NUM> may be <NUM> dB. The dynamic gain range of the preamplification stages <NUM>, <NUM> in combination with driving stage <NUM> and amplification stage <NUM> may be <NUM> dB to <NUM> dB. In some embodiments, fourth amplifier <NUM> may have a <NUM> W (+<NUM> dBm) maximum output power.

In addition to providing a wide dynamic gain range, RF interface board <NUM> may be configured to provide high resolution throughout the range. A digital-to-analog converter (DAC), which may be included in, or coupled to, board controller <NUM>, may be used to provide gain settings to one or more attenuators or amplifiers. In some embodiments, a DAC providing gain settings to first and second attenuators <NUM>, <NUM> may be used to provide an output RF electric signal with a step size less than or equal to <NUM> dB over an entire target output power range. The step size may be equal to about <NUM> dB. In some embodiments, a <NUM>-bit DAC may be used.

The target output power range may be selected based on the particular application. The target output power range may range from, for example, <NUM> mW to <NUM> W, or about five orders of magnitude. The target dB range, or power ratio between the high- and low-power output RF electric signals, may be at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> dB. One example of a target output power range is from <NUM> to <NUM> dBm. In some examples, the target output power range may have a low end of <NUM> dBm.

Contrary to other types of designs, the output RF electric signal may be substantially immune to changes in impedance load. For example, whether or not animal tissue is in the processing position, the output RF electric signal may not change (measurable using the forward power value). In some embodiments, the output RF electric signal changes less than +/- <NUM> dB whether or not animal tissue is in the processing position. The presence of animal tissue may represent an impedance match (e.g., about <NUM> ohms for a poultry claw) and the absence of animal tissue may represent a mismatch (e.g., open circuit). With the output RF electric signal being substantially immune to changes in impedance load, RF interface board <NUM> may not need to substantially change gain settings when animal tissue is placed in or removed from the processing position. However, in some embodiments, the board controller <NUM> may use the measured forward power value to maintain a constant power for output RF electric signal, for example, but adjusting gain settings.

<FIG> shows one example of a layout for sensing circuit <NUM>. Sensing circuit <NUM> may be operably coupled to circulator port <NUM>. Sensing circuit may include directional coupler <NUM> and power sensor <NUM>. Directional coupler <NUM> is configured to receive a power signal from circulator port <NUM>. Directional coupler <NUM> is configured to provide a sensing signal to coupling port <NUM>, which is isolated from the transmitted signal provided to through port <NUM>. Most of the energy from the power signal may be contained in the transmitted signal provided to through port <NUM>. The sensing signal may contain only a fraction of the power signal. In some embodiments, the sensing signal corresponds to -<NUM>, -<NUM>, or -<NUM> dB of the power signal. In some embodiments, the ratio of power at through port <NUM> to power at coupling port <NUM> is <NUM> to <NUM>, or about -<NUM> dB. Directional coupler <NUM> may also be described as a power divider. In general, the directional coupler <NUM> may desirably have tightly controlled coupling, low insertion loss, and an operation frequency range from <NUM> to <NUM>.

Power sensor <NUM> may be operably connected to coupling port <NUM> of directional coupler <NUM> to provide a power value based on the reduced-power sensing signal representing the power signal from circulator port <NUM>. Sensing circuit <NUM> may also include other components (not shown), such as an analog-to-digital converter (ADC) and a temperature sensor. Power sensor <NUM> may be coupled to an analog-to-digital converter (ADC), which may be considered part of sensing circuit <NUM> or board controller <NUM>. In some embodiments, board controller <NUM> may be described as a board control circuit, which may include one or more processors or microcontrollers.

Board controller <NUM> may be operably connected to power sensor <NUM> to receive the power value, which may represent a forward or reflected power value. Board controller <NUM> may be configured to provide a return loss value based on the forward and reflected power values. Board controller <NUM> may report the return loss value to system controller <NUM>.

<FIG> and <FIG> show one example of a physical layout for RF interface board <NUM>. As shown, RF interface board <NUM> is a printed circuit board, which may have multiple layers. <FIG> shows first major surface <NUM>, or top surface, of RF interface board <NUM>, and <FIG> shows second major surface <NUM>, or bottom surface, in a mirror view. Second major surface <NUM> is on an opposite side of RF interface board <NUM> from first major surface <NUM>. As used herein, the term "major surface" refers to a surface that is substantially parallel to each layer of the printed circuit board.

RF interface board <NUM> includes one or more regions. Each region may be partially or fully electromagnetically shielded, or isolated, from other regions using a housing. RF interface board <NUM> may include a ground trace <NUM>, or ground conductor, that extends between one or more regions to facilitate shielding. Ground trace <NUM> may be positioned on first major surface <NUM> and second major surface <NUM>. One or more apertures <NUM> may extend through ground trace <NUM>, which may be used to fasten an electromagnetic shielding structure to RF interface board <NUM>. The electromagnetic shielding structure may be used to create a compartment around each region to facilitate noise isolation of various components and may extend around the perimeter of RF interface board <NUM> to facilitate emissions control.

RF interface board <NUM> may include one or more of: first region <NUM>, second region <NUM>, third region <NUM>, fourth region <NUM>, fifth region <NUM>, sixth region <NUM>, seventh region <NUM>, eighth region <NUM>, and ninth region <NUM>. In the illustrated embodiment, all of the regions are positioned on the first major surface <NUM> except for eighth and ninth regions <NUM>, <NUM>, which are positioned on second major surface <NUM>.

On first major surface <NUM>, first region <NUM> may include board controller <NUM>. Second region <NUM> may include RF synthesizer circuit <NUM>. Third region <NUM> may include one or more preamplification stages <NUM>, <NUM>. Fourth region <NUM> may include driving stage <NUM>. Fifth region <NUM> may include amplification stage <NUM>. Sixth region <NUM> may include part of forward sensing circuit <NUM>. Seventh region <NUM> may include circulator <NUM> and part of reverse sensing circuit <NUM>.

On second major surface <NUM>, eighth region <NUM> may include part of forward sensing circuit <NUM>, such as power sensor <NUM> (<FIG>). Eighth region <NUM> may be positioned opposite to sixth region <NUM>. Ninth region <NUM> may include part of reverse sensing circuit <NUM>, such as power sensor <NUM> (different than power sensor <NUM> of forward sensing circuit <NUM>). Ninth region <NUM> may be positioned opposite to seventh region <NUM>.

Communication connection <NUM> may be operably connected to first region <NUM>, and output connection <NUM> may be operably connected to seventh region <NUM>.

The forward and reverse sensing circuits <NUM>, <NUM> may be accurate over the entire target output power range. In some embodiments, measurements of forward and reflected power values may be accurate within +/- <NUM> dB over an output power range from <NUM> to <NUM> dBm. Reflected power values may be accurate within +/- <NUM> dB over an even larger range, such as from <NUM> to <NUM> dBm, compared to forward power values. The accuracy of forward and reverse sensing circuits <NUM>, <NUM> may be maintained over one or more ISM frequency bands, such as the <NUM> to <NUM> ISM frequency band. The frequency of RF electric signal may be centered, or have a peak, at <NUM>. In other embodiments, the frequency of RF electric signal may be centered, or have a peak, at <NUM> within the <NUM> to <NUM> ISM frequency band.

Further, the forward and reverse sensing circuits <NUM>, <NUM> may be accurate within a target operating temperature range. In some embodiments, forward and reflected power values may accurate within +/- <NUM> dB over a temperature range of <NUM> to <NUM>. Using temperature sensors, the forward and reflected power values may be compensated to be accurate within +/- <NUM> dB.

<FIG> shows one method <NUM> for using RF interface board <NUM> in energy delivery system <NUM>. Method <NUM> may include synthesizing an RF electric signal <NUM>, which may also be described as a generated RF electric signal. The RF electric signal may have frequency content in one or more ISM frequency bands.

Method <NUM> may continue to attenuate and amplify the RF electric signal <NUM>. Some amplifiers may not provide accurate and precise gain control at low gains. Attenuators may be used to provide a dynamic gain range, particularly in the preamplification stage.

Method <NUM> may continue to provide a low-power or high-power electric signal to an RF applicator <NUM>. The low-power RF output electric signal may be used to generate a low-power alternating RF electric field using the RF applicator. The low-power field may be used for sensing the presence of animal tissue near the RF applicator. The high-power RF output electric signal may be used to generate a high-power alternating RF electric field using the RF applicator. The low-power field may be used for sensing animal tissue near the RF applicator.

<FIG> shows method <NUM>, which is one example for carrying out method <NUM> of <FIG>. Method <NUM> may include providing a low-power RF output electric signal to an RF applicator, such as RF applicator <NUM>, which may generate a low-power RF electric field <NUM>. Method <NUM> may continue and detect a return loss from the RF applicator <NUM>, which may be a baseline return loss corresponding to no animal tissue in the processing position of the RF applicator.

Animal tissue to be processed may be placed in the processing position of the RF applicator <NUM>. In some embodiments, the RF applicator may be moved to the animal tissue. In some embodiments, machine vision may be used to position animal tissue near the RF applicator.

The return loss detected after positioning the animal tissue may exceed a threshold value <NUM>. For example, the RF interface board may measure the return loss and communicate the return loss to the system controller. The return loss may be compared to a threshold value stored or determined by the system controller. When more than one RF applicator is used, for example, to detect more than one poultry claw, the average return loss associated with each RF applicator may be compared to the threshold value.

In some embodiments, the threshold value may be greater than or equal to <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> dB. When the measured return loss exceeds the threshold value, the system controller may issue a command to RF interface board to provide a high-power output RF electric signal, which may generate a high-power RF electric field to couple to the animal tissue <NUM>. The animal tissue may be processed in response to received energy from the high-power RF electric field.

When more than one RF applicator is used, each RF applicator may process tissue concurrently or sequentially. In other words, the high-power RF electric field may be provided to each RF applicator concurrently or at different times.

The system controller may issue a command to RF interface board to modify the frequency of the RF electric signal based on the detected return loss during processing <NUM>. The frequency content may be contained in one or more ISM frequency bands, even after being adjusted. In some embodiments, the board controller may sweep the frequency within one or more ISM frequency bands. For example, the frequency of the RF electric signal may be swept using the RF synthesizer circuit in the <NUM> to <NUM> ISM frequency band in increments of <NUM> or less (e.g., for finer control). The frequency resulting in the lowest return loss may be selected and used during delivery of the high-power RF electric field to the animal tissue. The frequency may be modified one or more times during delivery of the high-power RF electric field.

Method <NUM> may continue to switch into a monitoring mode, in which the high-power RF electric signal is switched to a low-power RF electric signal, to generate a low-power RF electric field <NUM>, once again, particularly when processing of the animal tissue has been completed. The RF interface board may be switched into a monitoring mode. In some embodiments, processing of the animal tissue may be completed after a predetermined duration or time period has elapsed. For example, the high-power RF electric signal may range from <NUM> to <NUM> W (e.g., about <NUM> to <NUM> dBm) and be delivered for about <NUM> second to process a poultry claw. In some embodiments, about <NUM> J of energy is delivered to each poultry claw.

The high-power output RF electric signal may be selected based on the particular application. In some embodiments, the high-power output RF electric signal may have power in a range from <NUM> to <NUM> W.

In some embodiments, detecting a baseline return loss <NUM> and detecting the return loss exceeding the threshold value <NUM> may include correcting the return loss value for compensate for drift. For example, the power sensor may drift due to changes in temperature or frequency.

<FIG> and <FIG> show plots of measured sensing power values (dBm) versus time (milliseconds) with and without high-power tracking mode, in which frequency is adjusted to match the load, using system <NUM> of <FIG> for one example of animal tissue. Plot <NUM> of <FIG> shows reflected power values <NUM> and calculated return losses <NUM> in response to forward power values <NUM> without the use of high-power tracking mode on the RF interface board. Plot <NUM> of <FIG> shows reflected power values <NUM> and calculated return losses <NUM> in response to forward power values <NUM> with high-power tracking mode turned on.

Forward power values <NUM> include sensing power values of <NUM> dBm starting at about -<NUM> milliseconds. Reflected power values <NUM>, <NUM> are high (corresponding to low return losses <NUM>, <NUM>) until the animal tissue is inserted into the receptacle and moved toward the processing position at about -<NUM> milliseconds. When the animal tissue is being positioned, a rapid decrease in reflected power values <NUM>, <NUM> (corresponding to increasing return losses <NUM>, <NUM>) is detected while the tissue is being properly positioned. Processing begins at <NUM> milliseconds. As illustrated, forward power values <NUM> climbs rapidly to the processing power of about <NUM> dBm and lasts for about <NUM> seconds.

In plot <NUM>, when high-power tracking mode is not used, reflected power values <NUM> may gradually increase during the first <NUM> milliseconds of processing, which may be due to tissue heating and may change from animal to animal. Large jumps in reflected power values <NUM> may be the result of physical movements of animal tissue relative to the RF applicator. Reflected power values <NUM> may continue to rise for the remainder of the processing time as the tissue continues to heat. Forward power may shut off at <NUM> milliseconds and forward power values <NUM> may drop when processing is complete.

In contrast to plot <NUM>, plot <NUM> shows the resulting reflected power values <NUM> and return losses <NUM> when high-power tracking mode is used. In general, the goal of high-power tracking mode may be to maintain a constant return loss throughout processing. As illustrated, reflected power values <NUM> and return losses <NUM> may remain constant, or substantially constant, from the start of processing at <NUM> milliseconds through the completion of processing at <NUM> milliseconds.

<FIG> shows one example of a second side of receptacle <NUM> different than the first side shown in FIG. In particular, the first side of receptacle <NUM> shown in FIG. 2A shows only half of the receptacle <NUM> shown in <FIG>. For example, FIG. 2A shows only three input connections <NUM>, or input connectors, whereas <FIG> shows six input connections <NUM> to deliver energy to all six poultry toes.

Receptacle <NUM> may also be described as a toe guide assembly. Receptacle <NUM> may include tuning board <NUM>, which may be a printed circuit board including various conductive paths and electrical components coupled to a substrate that deliver an RF electric signal from one or more input connections <NUM> to one or more RF applicators <NUM> (FIG. The receptacle <NUM> may be tuned for delivering RF energy to tissue positioned proximate to each RF applicator <NUM> using tuning board <NUM>.

In the illustrated embodiment, tuning board <NUM> is operably coupled to six input connections <NUM>. Although tuning board <NUM> is shown with six input connectors <NUM>, tuning board <NUM> may include any suitable number of input connections <NUM>. Each input connections <NUM> is operably coupled to a different conductor <NUM>. Each conductor <NUM> extends from input region <NUM> of receptacle <NUM> to applicator region <NUM> of receptacle <NUM>. Each conductor <NUM> is operably coupled to a different applicator connection <NUM>, which may include a solder joint through a via. In turn, each applicator connection <NUM> may be operably coupled to a different RF applicator <NUM>.

Conductors <NUM> may extend along any suitable path from input region <NUM> to applicator region <NUM>. In the illustrated embodiment, conductors <NUM> are generally straight and linear.

Each conductor <NUM> and corresponding applicator connection <NUM> may be separated from ground plane <NUM>, for example, by the absence of conductive material on the printed circuit board. In general, each conductor <NUM> is operably coupled, for example, to a corresponding ground plane <NUM> to form a <NUM>-ohm transmission line for an RF signal. Ground plane <NUM> may be electrically coupled to one or more grounding connection points, which are shown as conductive protrusions, or bolts, coupled to tuning board <NUM>. The grounding connection points may electrically couple ground plane <NUM> to an electromagnetically shielding housing.

One or more capacitors <NUM> may be positioned along one or more conductors <NUM>. In the illustrated embodiment, each capacitor <NUM> is electrically coupled between one conductor <NUM> and ground plane <NUM>. Each capacitor <NUM> may be used to tune a corresponding RF applicator <NUM> to reach a target frequency. In particular, placement of capacitor <NUM> along conductor <NUM>, for example, closer to input region <NUM> or closer to applicator region <NUM>, may change the resonant frequency of the corresponding RF applicator <NUM>.

Capacitors <NUM> may be described as tuning components. Although capacitors <NUM> are shown, any suitable tuning component may be used that is available to one skilled in the art who has the benefit of this disclosure. Non-limiting examples of other tuning components include inductors, wire, integrated circuit board capacitance, and quarter-wave matching.

<FIG> shows a flowchart of one example of a method for tuning a receptacle of the present disclosure. Method <NUM> may be used to tune a tissue guide or receptacle, such as receptacle <NUM> (<FIG>), to deliver RF energy at a target frequency to animal tissue. In general, the method includes adjusting a position of one or more capacitors along one or more conductors of a tuning board of the RF applicator to achieve a target resonant frequency. Each capacitor may be associated with one channel of the RF applicator.

Method <NUM> may include selecting an initial capacitor size <NUM>. Previous empirical data may be used to determine an initial capacitor size. For example, some capacitor sizes may range from <NUM> to <NUM> picofarads (pF).

The selected capacitor may be placed at a test location on the tuning board of the tissue guide <NUM> in method <NUM>. Previous empirical data may be used to determine an initial test location. The capacitor may be placed and operably coupled, for example, by soldering the capacitor between the respective conductor and the ground plane at the test location. Placing the capacitor may allow the capacitor to be electrically and mechanically coupled to one or more conductors at the test location.

Once the selected capacitor is placed, method <NUM> may include determining a resonant frequency of one or more channels on the tuning board and a corresponding power drop <NUM>. Any suitable technique to determine the resonant frequency may be used that is known to one skilled in the art having the benefit of this disclosure. In one example, the one or more channels may be analyzed using an RF vector network analyzer (VNA).

The electromagnetically shielding housing, or cover, of the tissue guide may be placed to cover the tuning board while the resonant frequency is determined. The housing may affect the characteristics of the tuning board.

A target frequency during tuning may be set a particular amount higher than a nominal frequency of a coupled RF interface board, such as RF interface board <NUM> (<FIG>), when tuning is performed without tissue in the processing position. The higher target frequency may facilitate a resonant frequency that is equal or substantially equal to the nominal frequency of the coupled RF interface board when tissue is placed in the processing position. In some embodiments, the target frequency may be set from <NUM> to <NUM> % higher than the nominal frequency of the RF interface board. For example, if the RF interface board <NUM> has an RF frequency centered at <NUM>, then the target frequency may be about <NUM>. The target frequency may be defined as the desired resonant frequency when the tissue guide is fully assembled (e.g., including electromagnetic shielding) without animal tissue present near the applicator.

Resonant frequency is generally a function of capacitor size and location along the conductor. In some embodiments, the resonant frequency may not be able to be determined by method <NUM>, for example, when the resonant frequency is outside of a desired range. In such cases, method <NUM> may return to selecting a new capacitor size <NUM> and placing the new capacitor at the test location <NUM>.

Method <NUM> may also include evaluating or analyzing the resonant frequency <NUM>. The capacitor may need to be moved, or repositioned to a different position, until the resonant frequency reaches the target frequency.

Method <NUM> may include moving the capacitor toward the input region <NUM> or to a position closer to the connector side, for example, in response to the resonant frequency being higher than the target frequency. Moving the capacitor toward the input region may lower the resonant frequency. The capacitor may be re-soldered at the new position.

Method <NUM> may also include moving the capacitor toward the applicator region <NUM> or to a position closer to the applicator region <NUM>, for example, in response to the resonant frequency being lower than the target frequency. Moving the capacitor toward the applicator region may raise the resonant frequency. The capacitor may be re-soldered at the new position.

Method <NUM> may include determining the return loss differential with, and without, animal tissue placed in the tissue guide <NUM>. For example, a poultry toe may be positioned to receive RF energy in the tissue guide, and a return loss in decibels may be measured. The measured return loss may be compared to measuring a return loss in decibels when the bird's toe is not positioned to receive RF energy in the tissue guide.

Method <NUM> may include determining whether the return loss differential is greater than a predetermined threshold <NUM>. The predetermined threshold may correspond to a desired difference between low-power and high-power RF energy. For example, the predetermined threshold may be equal to <NUM> decibels.

In some embodiments, in response to the return loss differential not exceeding the predetermined threshold, method <NUM> may return to selecting a new capacitor size <NUM> and placing the new capacitor at the test location <NUM>. If the return loss differential is less than the threshold, the tissue guide may not be sufficiently sensitive. Sensitivity may be affected by the shape of a curve (e.g., wide and flat versus narrow and tall) that represents the return loss differential versus frequency. For example, a wide and flat curve may result in lower sensitivity, and a narrow and tall curve may result in higher sensitivity.

In response to the return loss differential exceeding the predetermined threshold, method <NUM> may proceed to finish assembly of the tissue guide <NUM>. All the channels may be tuned before finally fastening the housing to cover the tuning board.

While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the specific illustrative embodiments provided below. Various modifications of the illustrative embodiments, as well as additional embodiments of the disclosure, will become apparent herein.

Thus, various embodiments of the ENERGY DELIVERY SYSTEM USING AN ELECTRIC FIELD are disclosed. Although reference is made herein to the accompanying set of drawings that form part of this disclosure, one of at least ordinary skill in the art will appreciate that various adaptations and modifications of the embodiments described herein are within, or do not depart from, the scope of this disclosure. For example, aspects of the embodiments described herein may be combined in a variety of ways with each other. Therefore, it is to be understood that, within the scope of the appended claims, the claimed invention may be practiced other than as explicitly described herein.

The terms "coupled" or "connected" refer to elements being attached to each other either directly (in direct contact with each other) or indirectly (having one or more elements between and attaching the two elements). Either term may be modified by "operatively" and "operably," which may be used interchangeably, to describe that the coupling or connection is configured to allow the components to interact to carry out at least some functionality (for example, a controller may be operably coupled to a DAC to provide data for conversion into an analog signal).

Terms related to orientation, such as "top" and "bottom," are used to describe relative positions of components and are not meant to limit the orientation of the embodiments contemplated. For example, an embodiment described as having a "top" and "bottom" also encompasses embodiments thereof rotated in various directions unless the content clearly dictates otherwise.

As used herein, "have," "having," "include," "including," "comprise," "comprising" or the like are used in their open-ended sense, and generally mean "including, but not limited to. " It will be understood that "consisting essentially of," "consisting of," and the like are subsumed in "comprising," and the like.

Claim 1:
A poultry processing system configured for stunting or retarding growth of poultry claws, beaks or bills, the system including:
an energy delivery system (<NUM>) comprising:
an RF synthesizer circuit (<NUM>) configured to generate an RF electric signal;
a preamplification stage (<NUM>, <NUM>) operably coupled to an output of the RF synthesizer circuit (<NUM>), wherein the preamplification stage (<NUM>, <NUM>) comprises an attenuator (<NUM>, <NUM>);
a board controller (<NUM>) operably coupled to the attenuator (<NUM>, <NUM>) of the preamplification stage (<NUM>, <NUM>), wherein the board controller (<NUM>) is configured to modify a gain setting of the attenuator (<NUM>, <NUM>);
an output connection (<NUM>) configured to provide a low-power signal or a high-power signal based on at least the RF electric signal and the gain setting of the attenuator (<NUM>, <NUM>); and
an RF applicator (<NUM>) operably coupled to the output connection (<NUM>), wherein the low-power signal or the high-power signal is configured to be provided to the RF applicator (<NUM>) configured to couple an alternating low-power or high-power RF electric field to animal tissue for respectively sensing the presence of, or processing, the animal tissue,
wherein the animal tissue is a poultry claw, beak or bill,
wherein the board controller (<NUM>) is configured to:
provide a first gain setting of the attenuator (<NUM>, <NUM>) to provide the low-power signal at the output connection (<NUM>) and measuring a baseline return loss value corresponding to no animal tissue in a processing position of the RF applicator (<NUM>); and
provide a second gain setting of the attenuator (<NUM>, <NUM>) having a lower magnitude than a magnitude of the first gain setting to provide the high-power signal at the output connection (<NUM>) in response to detecting a return loss value exceeding a loss threshold value, wherein a return loss value exceeding the loss threshold value corresponds to animal tissue in the processing position of the RF applicator (<NUM>).