Pressure sensor assemblies and methods of detecting pressure within an engine

A pressure sensing system and method for an engine of an aircraft include a transceiver assembly coupled to a portion of the engine, and a pressure sensor assembly coupled to a fan blade of the engine. The transceiver assembly is configured to transmit a first signal at a first frequency and a second signal at a second frequency that differs from the first frequency. The pressure sensor assembly is configured to receive the first signal and the second signal and transmit a third signal at a third frequency that is a difference between the first frequency of the first signal and the second frequency of the second signal. The transceiver assembly is configured to receive the third signal at the third frequency. A pressure in relation to the engine is determined based on the third signal.

FIELD OF EMBODIMENTS OF THE DISCLOSURE

Embodiments of the present disclosure generally relate to systems and methods for sensing pressure generated in relation to components, such as aircraft engines, and, more particularly, to pressure sensor assemblies, such as microelectromechanical pressure sensor assemblies.

BACKGROUND OF THE DISCLOSURE

Microphones are commonly used to measure sound pressure levels within one or more acoustic bandwidths of interest. For example, in various aeronautical and aerospace vehicles, microphones may be used to measure sound pressure levels within engines. The sound pressure levels detected by a microphone may be used to monitor engine performance. For example, the sound pressure levels may be analyzed to detect potential irregularities.

Existing microphones include internal (or local) electronics for signal processing. However, such electronics may not be able to effectively operate at elevated temperatures, such as may be generated within engines of an aircraft. As an alternative, optical-based microphones may be used. However, while optical-based microphones are generally able to operate at higher temperatures, many known optical-based microphones are expensive, and typically difficult to package. Further, optical-based microphones are connected to fibers, which may limit areas where they can be placed.

SUMMARY OF THE DISCLOSURE

A need exists for an improved sensor and method for detecting pressure, such as within an engine of an aircraft.

With that need in mind, certain embodiments of the present disclosure provide a pressure sensor assembly including a first receive antenna array configured to receive a first signal at a first frequency, and a second receive antenna array configured to receive a second signal at a second frequency that differs from the first frequency. A diode is coupled to both the first receive antenna array and the second receive antenna array. The diode is configured to receive the first signal at the first frequency and the second signal at the second frequency and output a third signal at a third frequency that is a difference between the first frequency and the second frequency. A transmit antenna array is coupled to the diode. The transmit antenna array is configured to receive the third signal at the third frequency and output the third signal at the third frequency.

In at least one embodiment, the pressure sensor assembly also includes a first substrate. The first receive antenna array, the second receive antenna array, and the transmit antenna array are disposed on the first substrate.

In at least one example, the pressure sensor assembly also includes a first microstrip feed that connects the transmit antenna array to the diode, and a second microstrip feed that connects the first receive antenna array and the second receive antenna array to the diode.

The first receive antenna array and the second receive antenna array may operate in a W-band, and the transmit antenna array may operate in an X-band.

The diode may be a p-n junction diode, a PIN diode, a Schottky diode, a Zener diode, or a tunnel diode. One or more of the first receive antenna array, the second receive antenna array, or the transmit antenna array may be edge-fed in relation to the diode. One or more of the first receive antenna array, the second receive antenna array, or the transmit antenna array may be proximity-coupled in relation to the diode.

In at least one embodiment, at least one cavity is disposed within at least one substrate underneath at least a portion of one or more of the first receive antenna array, the second receive antenna array, or the transmit antenna array. For example, a first cavity may be within the substrate(s) underneath at least a portion of one or both of the first receive antenna array or the second receive antenna array.

In at least one embodiment, a vent channel is formed through and extending within the substrate(s). The vent channel is fluidly connected to the first cavity. A vent outlet is formed within the substrate(s). The vent outlet is fluidly connected to the vent channel.

As another example, a first cavity is within the substrate(s) underneath at least a portion of the transmit antenna array. As another example, a first cavity is within the substrate(s) underneath at a least a portion of one or both of the first receive antenna array or the second receive antenna array, and a second cavity is within the substrate(s) underneath at least a portion of the transmit antenna array.

In at least one embodiment, at least one diaphragm is positioned over the cavity.

In at least one embodiment, a first substrate is a P-type doped semiconductor substrate. A first N-type impurity is doped on the first substrate. A second N-type impurity is doped on the first N-type impurity to form, at least in part, the diode. An oxidation layer is deposited over the first substrate. A metal is deposited over the oxidation layer to form the first receive antenna array, the second receive antenna array, a first microstrip feed, a second microstrip feed, the transmit antenna array, and electrical contacts. A first cavity, a vent channel, and a vent outlet are formed into the first substrate. A backside ground plane is deposited onto the second substrate. The second substrate is bonded to the first substrate.

In at least one embodiment, a first substrate is an intrinsic semiconducting substrate. The first substrate is doped with a first P-type impurity. A first N-type impurity is doped over a portion of the first P-type impurity on the first substrate. A second P-type impurity is doped over a portion of the first N-type impurity to define, at least in part, the diode. A passivation layer is deposited over the first substrate. A first metal layer forms electronic contacts deposited over the passivation layer. A second metal layer forms a microstrip feed network deposited over the first metal layer. A third metal layer forms a backside ground plane deposited on the first substrate opposite from the second metal layer. A fourth metal layer forms the first receive antenna array, the second receive antenna array, and the transmit antenna array on a second substrate. At least one cavity is formed in the first substrate or the second substrate.

Certain embodiments of the present disclosure provide a pressure sensing method that includes providing a first receive antenna array that receives a first signal at a first frequency, providing a second receive antenna array that receives a second signal at a second frequency that differs from the first frequency, coupling a diode to the first receive antenna array and the second receive antenna array, coupling a transmit antenna array to the diode, receiving (by the diode) the first signal at the first frequency and the second signal at the second frequency, outputting (by the diode) a third signal at a third frequency that is a difference between the first frequency and the second frequency, receiving (by the transmit antenna array from the diode) the third signal at the third frequency, and outputting (by the transmit antenna array) the third signal at the third frequency.

In at least one embodiment, the outputting, by the transmit antenna array, includes outputting the third signal at the third frequency to a receiver. The pressure sensing method further includes determining, by the receiver, a pressure level from the third signal at the third frequency.

In at least one embodiment, the pressure sensing method also includes disposing the first receive antenna array, the second receive antenna array, and the transmit antenna array on a first substrate.

In at least one embodiment, the pressure sensing method also includes connecting, by a first microstrip feed, the transmit antenna array to the diode, and connecting, by a second microstrip feed, the first receive antenna array and the second receive antenna array to the diode.

The pressure sensing method may also include operating the first receive antenna array and the second receive antenna array in a W-band, and operating the transmit antenna array in an X-band.

The pressure sensing method may also include disposing at least one cavity within at least one substrate underneath at least a portion of one or more of the first receive antenna array, the second receive antenna array, or the transmit antenna array. Further, the pressure sensing method may include forming a vent channel within the at least one substrate, wherein the vent channel is fluidly connected to the at least one cavity, and forming a vent outlet within the at least one substrate, wherein the vent outlet is fluidly connected to the vent channel.

The pressure sensing method may also include positioning at least one diaphragm over the at least one cavity.

In at least one embodiment, the pressure sensing method further includes providing a first substrate that is a P-type doped semiconductor substrate, doping a first N-type impurity on the first substrate, doping a second N-type impurity on the first N-type impurity to form, at least in part, the diode, depositing an oxidation layer over the first substrate, depositing a metal over the oxidation layer to form the first receive antenna array, the second receive antenna array, a first microstrip feed, a second microstrip feed, the transmit antenna array, and electrical contacts, laser etching a first cavity, a vent channel, and a vent outlet into the first substrate, depositing a backside ground plane onto a second substrate, and/or bonding the second substrate to the first substrate.

In at least one embodiment, the pressure sensing method includes providing a first substrate that is an intrinsic semiconducting substrate, doping the first substrate with a first P-type impurity, doping a first N-type impurity over a portion of the first P-type impurity on the first substrate, doping a second P-type impurity over a portion of the first N-type impurity to define, at least in part, the diode, depositing a passivation layer over the first substrate, depositing a first metal layer over the passivation layer to form electronic contacts, depositing a second metal layer over the first metal layer to form a microstrip feed network, depositing a third metal layer on the first substrate opposite from the second metal layer to form a backside ground plane, depositing a fourth metal layer on a second substrate to form the first receive antenna array, the second receive antenna array, and the transmit antenna array, and/or forming at least one cavity in the first substrate or the second substrate. The forming the at least one cavity step may include forming a first cavity formed in the first substrate underneath at least a portion of the transmit antenna array, and forming a second cavity in the second substrate underneath at least a portion of one or both of the first receive antenna array or the second receive antenna array. The pressure sensing method may also include bonding the first substrate to the second substrate.

Certain embodiments of the present disclosure provide a pressure sensing method that includes receiving (by a first receive antenna array) a first signal at a first frequency, receiving (by a second receive antenna array) a second signal at a second frequency that differs from the first frequency, receiving (by a diode) the first signal at the first frequency and the second signal at the second frequency, outputting (by the diode) a third signal at a third frequency that is a difference between the first frequency and the second frequency, receiving (by a transmit antenna array from the diode) the third signal at the third frequency, and outputting (by the transmit antenna array) the third signal at the third frequency.

Certain embodiments of the present disclosure provide a pressure sensing system for an engine of an aircraft. The pressure sensing system includes a transceiver assembly coupled to a portion of the engine, and a pressure sensor assembly coupled to a fan blade of the engine. The transceiver assembly is configured to transmit a first signal at a first frequency and a second signal at a second frequency that differs from the first frequency. The pressure sensor assembly is configured to receive the first signal and the second signal and transmit a third signal at a third frequency that is a difference between the first frequency of the first signal and the second frequency of the second signal. The transceiver assembly is configured to receive the third signal at the third frequency. A pressure in relation to the engine is determined based on the third signal.

In at least one embodiment, the transceiver assembly includes a first transmit antenna array configured to transmit the first signal, a second transmit antenna array configured to transmit the second signal, and a receive antenna array configured to receive the third signal.

The pressure sensor assembly may include a radio frequency identification (RFID) tag. In at least one embodiment, the pressure sensor assembly is mounted on the fan blade.

In at least one embodiment, a pressure determination control unit determines the pressure by analyzing the third signal. The transceiver assembly may include the pressure determination control unit.

In at least one embodiment, one or more waveguides extend into a housing of the engine. The first signal and the second signal are transmitted through the one or more waveguides. The third signal is received through the one or more waveguides.

As an example, the one or more waveguides include a first waveguide, a second waveguide, and a third waveguide. The first signal is transmitted through the first waveguide. The second signal is transmitted through the second waveguide. The third signal is received through the third waveguide.

Certain embodiments of the present disclosure provide a pressure sensing method for an engine of an aircraft. The pressure sensing method includes coupling a transceiver assembly to a portion of the engine; coupling a pressure sensor assembly to a fan blade of the engine; transmitting, from the transceiver assembly, a first signal at a first frequency and a second signal at a second frequency that differs from the first frequency; receiving, by the pressure sensor assembly, the first signal and the second signal; transmitting, by the pressure sensor assembly, a third signal at a third frequency that is a difference between the first frequency of the first signal and the second frequency of the second signal; receiving, by the transceiver assembly, the third signal at the third frequency; and determining the pressure in relation to the engine based on the third signal.

In at least one embodiment, said transmitting, by the transceiver assembly, includes transmitting, by a first transmit antenna array, the first signal; and transmitting, by a second transmit antenna array, the second signal. In at least one embodiment, said receiving, by the transceiver assembly, includes receiving, by a receive antenna array, the third signal.

In at least one embodiment, the pressure sensing method includes extending one or more waveguides extending a housing of the engine. Said transmitting, from the transceiver assembly, includes transmitting the first signal and the second signal through the one or more waveguides. Said receiving, by the transceiver assembly, includes receiving the third signal through the one or more waveguides.

As an example, said transmitting from the transceiver assembly includes transmitting the first signal through a first waveguide, and transmitting the second signal through a second waveguide. Further, said receiving, by the transceiver assembly, includes receiving the third signal through a third waveguide.

Certain embodiments of the present disclosure provide an aircraft including an engine including a housing and a fan blade within the housing, and a pressure sensing system, as described herein.

DETAILED DESCRIPTION OF THE DISCLOSURE

Certain embodiments of the present disclosure provide a pressure sensor assembly. The pressure sensor assembly may be passive in that it may not include an internal energy source, such as a battery. The pressure sensor assembly is also configured to wirelessly operate. In at least one embodiment, the pressure sensor assembly is configured to operate in the far-field and is interrogated with linear or circular electromagnetic plane waves in two frequency bands. A portion of the incident electromagnetic plane waves is reflected back at a difference frequency to a receiver. The signal is then processed to determine the sound pressure level within an acoustic bandwidth of interest. The pressure sensor may be fabricated using subtractive (for example, milling, wet etching, and/or laser etching) and additive (for example, printing or film deposition) methods. In at least one embodiment, the pressure sensor assembly may be formed of materials that are able to withstand elevated temperatures, such as temperatures generated within engines of aircraft. For example, the pressure assembly may include antennas formed of platinum or titanium, and one or more substrates formed of silicon carbide. In general, the pressure sensor assembly is capable of operating in harsh environments, such as high temperatures, corrosive, and/or radiative environments.

In at least one embodiment, the pressure sensor assembly includes circularly polarized antennas, which minimize or otherwise reduce power loss between the pressure sensor assembly and a transceiver. The pressure sensor assembly includes a first receive antenna array and a second receive antenna array for receiving signals (such as radio frequency signals) at two different frequencies. The pressure sensor assembly also includes a third antenna array (a transmit antenna array) for broadcasting a signal at a frequency that is the difference between the two frequencies of the received signals. In at least one embodiment, the pressure sensor assembly also includes an integrated diode (for example, a high temperature, high frequency diode) for producing a difference frequency. The pressure sensor assembly may be adapted to linearly polarized and circularly polarized antenna types.

Certain embodiments of the present disclosure provide a pressure sensor assembly that includes a first receive antenna array configured to receive a first signal at a first frequency, a second receive antenna array configured to receive a second signal at a second frequency that differs from the first frequency, and a diode coupled to (for example, electrically connected to) the first receive antenna array and the second receive antenna array. The diode is configured to receive the first signal at the first frequency and the second signal at the second frequency and output a third signal at a third frequency that is a difference between the first frequency and the second frequency. A transmit antenna array is also coupled to (for example, electrically connected to) the diode. The transmit antenna array is configured to receive the third signal at the third frequency and output the third signal at the third frequency to a transceiver assembly configured to determine a pressure level (such as a sound pressure level) from the third signal at the third frequency. In at least one embodiment, the pressure sensor assembly also includes at least one acoustic cavity disposed within at least one substrate underneath at least a portion of one or more of the first receive antenna array, the second receive antenna array, or the transmit antenna array.

Certain embodiments of the present disclosure provide a method of measuring dynamic pressure, such as within an engine of an aircraft. The method includes transmitting two electromagnetic plane waves at different frequencies to a passive wireless pressure sensor. Portions of the incident electromagnetic plane waves are reflected back at a difference frequency to a receiver. The signal is then processed, such as by a pressure determination control unit, to determine a sound pressure level at an acoustic frequency of interest.

In at least one embodiment, a pressure sensing system and method includes waveguides coupled to a housing of an engine, such as a turbine engine. A sensor is coupled to a fan blade of an engine.

FIG. 1illustrates a schematic box diagram of a pressure sensing system100, according to an embodiment of the present disclosure. The pressure sensing system100includes a transceiver assembly102that includes a housing104that retains a first transmit antenna array106, a second transmit antenna array108and a receive antenna array110. The first transmit antenna array106and the second transmit antenna array108are coupled to (for example, electrically connected to) a transmitter112, such as through one or more wired or wireless connections. The receive antenna array110is coupled to (for example, electrically connected to) a receiver114, such as through one or more wired or wireless connections. The receiver is coupled to (for example, electrically connected to) a display116, such as through one or more wired or wireless connections. The display116may be a monitor, screen (such as a digital, light emitting diode (LED), liquid crystal display (LCD) screen, or the like), a touchscreen interface, and/or the like.

The pressure sensing system100also includes a pressure sensor assembly120that is configured to detect pressure, such as sound pressure, generated by, within, or otherwise near a component122. In at least one embodiment, the pressure sensor assembly120is a sensor tag. For example, the sensor tag is or otherwise includes a radio frequency identification (RFID) tag.

In at least one embodiment, the pressure sensor assembly120is mounted to a portion of the component122. In at least one embodiment, the pressure sensor assembly120is within the component122. In at least one embodiment, the pressure sensor assembly120is separated from the component122. For example, the pressure sensor assembly120may be mounted proximate to (such as within 10 feet or less) of the component122. The component122may be various structures, devices, assemblies, systems, or the like that generate sound pressure or otherwise reside in a sound pressure environment. For example, the component122may be an engine of an aircraft. In at least one embodiment, the component122is an engine, such as a turbine engine of an aircraft. As an example, the pressure sensor assembly120is secured to (for example, mounted to, embedded in, and/or the like) a fan blade of the engine.

In at least one other embodiment, the component122may be a speaker or other such audio device. In at least one other embodiment, the component122may be a portion of heating, ventilation, and air conditioning (HVAC) systems. It is to be understood that these are merely examples of components, and that the pressure sensor assembly120may be used with respect to any type of component that generates pressure, such as sound pressure, which may be analyzed to determine an operational status of the component.

In operation, the transmitter112provides a first time-varying power signal to the first transmit antenna array106, which in response, transmits a first signal128(such as a first RF signal) at a first frequency. Similarly, the transmitter112provides a second time-varying power signal to the second transmit antenna array108, which in response, transmits a second signal130(such as a second RF signal) at a second frequency that differs from the first frequency. In at least one embodiment, the first frequency and the second frequency are in a common frequency band. For example, the first frequency may be at 85 GHz, while the second frequency may be at 75 GHz. In at least one other embodiment, the first frequency may be within a first frequency band (for example, W-band), while the second frequency may be within a second frequency band that differs from the first frequency band (for example, K-band).

The first signal128and the second signal130are transmitted across free space and interact with the pressure sensor assembly120such that the pressure sensor assembly120transmits a third signal132, such as a third radio frequency signal (which is transmitted at a third frequency that is a difference between the first frequency of the first signal128and the second frequency of the second signal130). As an example, if the first signal128is at 85 GHz, and the second signal130is at 75 GHz, the pressure sensor assembly120transmits or otherwise outputs the third signal132at 10 GHz.

The receive antenna array110of the transceiver assembly102receives the third signal132. As the third signal132is received by the receive antenna array110, a third time-varying power signal is generated at the receiver114. By receiving the third signal132at the third frequency, which is the difference between the first frequency of the first signal128and the second frequency of the second signal130, the receiver114is able to detect pressure (such as sound pressure) generated in relation to (for example, by, within, at, or near) the component122, as described herein. The receiver114outputs a signal134to the display116, which, in turn, shows an indication of the pressure generated by the component122and detected by the pressure sensor assembly120. Optionally, the receiver114may be coupled to (for example, electrically connected to) an audio device, such as a speaker, which emits an audio signal in response to reception of the signal134to indicate the pressure generated in relation to the component122.

In at least one embodiment, the transceiver assembly102includes a pressure determination control unit115. For example, the pressure determination control unit115is in communication with the receiver114through one or more wired or wireless connections. As another example, the receiver114includes the pressure determination control unit115. In at least one other embodiment, the transceiver assembly102does not include the pressure determination control unit115. In such embodiments, the pressure determination control unit115is remotely located from the transceiver assembly102and is in communication with the receiver114, such as through one or more wired or wireless connections.

The pressure determination control unit115analyzes the third signal132at the third frequency, which is the difference between the first frequency of the first signal128and the second frequency of the second signal130, and determines a sound pressure level at an acoustic frequency signal of interest. For example, the pressure determination control unit115correlates a magnitude and phase of the third signal132, such as in relation to the first signal128and the second signal130, with pressure. The pressure determination control unit115is in communication with, and/or includes a memory that stores calibrated pressure levels that are correlated with magnitude and/or phases. In this manner, the pressure determination control unit115is able to determine a pressure through analysis of a magnitude and/or phase of the third signal132.

As used herein, the term “control unit,” “central processing unit,” “unit,” “CPU,” “computer,” or the like can include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. Such are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of such terms. For example, the pressure determination control unit115can be or include one or more processors that are configured to control operation thereof, as described herein.

The control unit(s), such as the pressure determination control unit115, are configured to execute a set of instructions that are stored in one or more data storage units or elements (such as one or more memories), in order to process data. For example, the pressure determination control unit115can include or be coupled to one or more memories. The data storage units can also store data or other information as desired or needed. The data storage units can be in the form of an information source or a physical memory element within a processing machine. The one or more data storage units or elements can comprise volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. As an example, the nonvolatile memory can comprise read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), and/or flash memory and volatile memory can include random access memory (RAM), which can act as external cache memory. The data stores of the disclosed systems and methods is intended to comprise, without being limited to, these and any other suitable types of memory.

The set of instructions can include various commands that instruct the control unit(s), such as the pressure determination control unit115, as a processing machine to perform specific operations such as the methods and processes of the various embodiments of the subject matter described herein. The set of instructions can be in the form of a software program. The software can be in various forms such as system software or application software. Further, the software can be in the form of a collection of separate programs, a program subset within a larger program or a portion of a program. The software can also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine can be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

The diagrams of embodiments herein can illustrate one or more control or processing units, such as the pressure determination control unit115. It is to be understood that the processing or control units can represent circuits, circuitry, or portions thereof that can be implemented as hardware with associated instructions (e.g., software stored on a tangible and non-transitory computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like) that perform the operations described herein. The hardware can include state machine circuitry hardwired to perform the functions described herein. Optionally, the hardware can include electronic circuits that include and/or are connected to one or more logic-based devices, such as microprocessors, processors, controllers, or the like. Optionally, the control unit(s), such as the pressure determination control unit115, can represent processing circuitry such as one or more of a field programmable gate array (FPGA), application specific integrated circuit (ASIC), microprocessor(s), and/or the like. The circuits in various embodiments can be configured to execute one or more algorithms to perform functions described herein. The one or more algorithms can include aspects of embodiments disclosed herein, whether or not expressly identified in a flowchart or a method.

As used herein, the terms “software” and “firmware” are interchangeable, and include any computer program stored in a data storage unit (for example, one or more memories) for execution by a computer, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above data storage unit types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.

FIG. 2illustrates a perspective top view of the pressure sensor assembly120, according to an embodiment of the present disclosure. The pressure sensor assembly120includes a first receive antenna array140, a second receive antenna array142, and a transmit antenna array144disposed on a substrate150(for example, a first substrate), and are coupled to a backside ground plane152. A first microstrip feed146electrically connects the transmit antenna array144to a diode148, which, in turn, electrically connects to a second microstrip feed147that electrically connects to the first receive antenna array140and the second receive antenna array142.

In at least one embodiment, the first receive antenna array140is a W-band antenna array including antenna elements154(for example, four antenna elements) that electrically connect to the second microstrip feed147. The first receive antenna array140is configured to operate at or near 85 GHz. The antenna elements154may include circular main bodies153with internal slots155. As shown, the first receive antenna array140includes an edge-fed microstrip feed network156that electrically connects to the second microstrip feed147. Optionally, the first receive antenna array140may include more or less antenna elements than shown, having different shapes than shown, which may or may not include internal slots, and may be configured to operate at or near a frequency that is greater or less than 85 GHz. Referring toFIGS. 1 and 2, the first receive antenna array140is configured to receive the first signal128transmitted at the first frequency by the first transmit antenna array106.

In at least one embodiment, the second receive antenna array142is a W-band antenna array including antenna elements158(for example, four antenna elements) that electrically connect to the second microstrip feed147. The second receive antenna array142is configured to operate at or near 75 GHz. The antenna elements154may include circular main bodies157having internal slots159. As shown, the second receive antenna array142includes an edge-fed microstrip feed network160that electrically connects to the second microstrip feed147. Optionally, the second receive antenna array142may include more or less antenna elements than shown, having different shapes than shown, which may or may not include internal slots, and may be configured to operate at or near a frequency that is greater or less than 75 GHz. Referring toFIGS. 1 and 2, the second receive antenna array142is configured to receive the second signal130transmitted at the second frequency by the second transmit antenna array108.

In at least one embodiment, the transmit antenna array144is an X-band antenna. The transmit antenna array144includes a square-shaped antenna element170having an internal slot172. Optionally, the transmit antenna array144may be sized and shaped differently than shown. For example, the transmit antenna array144may be circular. The antenna element170electrically connects to, or otherwise includes, the first microstrip feed146. Referring toFIGS. 1 and 2, the transmit antenna array144is configured to transmit the third signal132at the third frequency, which is the difference between the first frequency and the second frequency.

As shown, the diode148couples to (for example, electrically connects to) the first microstrip feed146and the second microstrip feed147. Accordingly, the diode148is disposed between the transmit antenna array144and the first and second receive antenna arrays140and142. The diode148is a non-linear device that generates a signal, such as a radio frequency signal, having the third frequency, which is difference between the first frequency of the first signal128received by the first receive antenna array140and the second frequency of the second signal130received by the second receive antenna array142. As such, the diode148is configured to generate the third signal132, which is received by the transmit antenna array144and transmitted to the transceiver assembly102.

The first and second signals128and130, respectively, are fed to the diode148via the second microstrip feed147. In general, the diode148exhibits a switch-like behavior. Consider, for example, a contact switch with an input, an output, and a contact position. A square wave input signal (at a first frequency) with the contact position being turned on and off (at a second frequency) generates a square wave output signal (at any instantaneous time) that corresponds to the overlap between the input signal and the contact position (that is, on or off). Over time, the output signal reveals frequency components including fundamentals, sum and difference terms, harmonics, and intermodulation products. In general, the diode148receives the first signal128at the first frequency and the second signal130at the second frequency, and outputs the third signal132at the third frequency (that is, the difference frequency) to the transmit antenna array144via the first microstrip feed146.

The diode148may be a p-n junction diode, a PIN diode, a Schottky diode, a Zener diode, or tunnel diode, or the like. For example, the diode148may be a p-n junction diode, which has an electrically-capacitive depletion region when no voltage is applied across an anode and cathode of the diode148. When a voltage is applied across the anode and cathode, electrical current flows therethrough. As another example, the diode148may be a Schottky diode, which is similar to the p-n junction diode, but exhibits a lower required voltage to allow current to flow, which thereby results in higher switching performance, and may be well suited for high-frequency applications.

FIG. 3illustrates a top view of the pressure sensor assembly120. The substrate150is shown as transparent so that internal components are shown. In particular, a circular-shaped cavity174(for example, a circular-shaped acoustic cavity) is positioned underneath the first receive antenna array140. Optionally, the cavity174may be sized and shaped differently than shown. For example, the cavity174may be square-shaped. The cavity174may be formed within the substrate150. The cavity174may extend underneath an entirety of the first receive antenna array140, and at least a portion of the second microstrip feed147. Optionally, the cavity174may be underneath less than all of the first receive antenna array140. In at least one other embodiment, the cavity174is disposed underneath at least a portion of the second receive antenna array142. In at least one other embodiment the cavity174is disposed underneath at least portions of both the first receive antenna array140and the second receive antenna array142. In at least one other embodiment, the cavity174may be disposed underneath at least a portion of the transmit antenna array144. In at least one other embodiment, a first cavity is disposed underneath at least a portion of one or both of the first receive antenna array140and/or the second receive antenna array142, and a second cavity is disposed underneath at least a portion of the transmit antenna array144.

The cavity174fluidly connects to a vent channel176that is formed and extends within the substrate150. The vent channel176may include a series of turns178. The vent channel176may include more or less turns178than shown. A terminal end180of the vent channel176fluidly connects to a vent outlet182formed in the substrate150. The vent outlet182includes a vent hole184that is formed through an upper surface186of the substrate150.

As shown, the vent outlet182may be formed in the substrate150between the first receive antenna array140and the transmit antenna array144. Optionally, the vent outlet182and the vent channel176may be distally away from the transmit antenna array144, such as toward an edge185of the substrate150.

In at least one embodiment, an optional bandwidth enhancing cavity (such as the cavity500shown inFIG. 20) may be formed underneath at least a portion of the transmit antenna array144. It has been found that the optional bandwidth enhancing cavity underneath the transmit antenna array144increases gain and bandwidth of the transmit antenna array144. A bandwidth enhancing cavity may also be formed underneath at least a portion of one or both of the first receive antenna array140and/or the second receive antenna array142.

FIG. 4illustrates a cross-sectional view of the pressure sensor assembly120through line4-4ofFIG. 2. Referring toFIGS. 1-4, the substrate150includes a diaphragm190positioned over the cavity174. The diaphragm190is between the cavity174and the first receive antenna array140(and/or the second receive antenna array142). The first receive antenna array140and the second receive antenna array142each have an electrical resonant frequency determined primarily by the capacitance between the first receive antenna array140(and/or the second receive antenna array142) and the backside ground plane152. The electrical resonant frequency of the first receive antenna array140(and/or the second receive antenna array142) changes as a function of displacement of the diaphragm190above the cavity174moving back and forth due to an external sound pressure level192. The change in the electrical resonant frequency of the first receive antenna array140(and/or the second receive antenna array142) changes the frequency of the third signal132, as generated by the diode148, and transmitted by the transmit receive antenna array144. The third signal132is received by the receive antenna array110of the transceiver assembly102, and the receiver114is configured to determine the external sound pressure level192in response to the third signal132, as a function of variation of the third signal132. For example, the third signal132at the third frequency varies in response when there is no external sound pressure, while the third signal132at the third frequency varies in response to the sound pressure level192. The third signal132having the variation is correlated with and/or differentiated from the third signal132with no variation.

In at least one embodiment, in order to form the pressure sensor assembly120, the substrate150may be provided as a P-type doped semiconductor substrate. The diode148is formed on and/or within the substrate150by doping with an N-type impurity194(for example, a first N-type impurity). Then, an N+-type impurity196(for example, a second N-type impurity) is doped on the N-type impurity194. An oxidation layer198may then be deposited over the substrate150having a first channel200over the N-type impurity194and a second channel202over the N+ type impurity196. The N-type impurity194and the N+-type impurity define junctions of the diode148. The oxidation layer198provides electrical insulation for electrical pads.

Next, metal is deposited over the oxidation layer198to form the first receive antenna array140, the second receive antenna array142, the first microstrip feed146, the second microstrip feed147, the transmit antenna array144, and electrical contacts204and206within the first channel200and the second channel202, respectively. Next, the cavity174, the vent channel176, and the vent outlet182are formed through the substrate opposite from the oxidation layer198, such as via laser etching, milling, cutting, or the like. Subsequently, a metal layer is deposited on a second substrate210to form the backside ground plane152. The second substrate210is then bonded to the first substrate150.

The pressure sensor assembly120shown and described with respect toFIGS. 1-4includes the first receive antenna array140, the second receive antenna array142, and the transmit antenna array144. The cavity174may be disposed underneath one or both of the first receive antenna array140and/or the second receive antenna array142, thereby forming the diaphragm190, which moves in response to acoustic pressure. The diode148is formed on and/or within the substrate150and connects the first receive antenna array140and the second receive antenna array142to the transmit antenna array144. The first receive antenna array140, the second receive antenna array142, and the transmit antenna array144are edge fed over the substrate150. The diode148may be formed within the substrate150, while the first receive antenna array140, the second receive antenna array142, and the transmit antenna array144are disposed above the substrate150.

In at least one embodiment, the first receive antenna array140, the second receive antenna array142, and the transmit antenna array144are edge-fed with respect to the diode148. Further, in at least one embodiment, the diode148is a Schottky diode. In at least one other embodiment, the diode148is a p-n junction diode.

In at least one embodiment, the first receive antenna array140, the second receive antenna array142, and the transmit antenna array144are proximity coupled to the diode148. Further, in at least one embodiment, the diode148is a Schottky diode. In at least one other embodiment, the diode148is a p-n junction diode.

FIG. 5illustrates a perspective top view of the pressure sensor assembly120, according to an embodiment of the present disclosure. As shown, the transmit antenna array144may have a circular shape. Optionally, the transmit antenna array144may be shaped differently, such as rectangular.

FIG. 6illustrates a cross-sectional view of a first substrate300, according to an embodiment of the present disclosure. In order to form the pressure sensor assembly120shown inFIG. 5, the first substrate300is first provided. The first substrate300may be an intrinsic semiconducting substrate.

FIG. 7illustrates a cross-sectional view of the first substrate300doped with a P-type impurity302(for example, a first P-type impurity), according to an embodiment of the present disclosure. The P-type impurity302may be disposed over an entire upper surface304of the first substrate300.

FIG. 8illustrates a cross-sectional view of an N-type impurity306(for example, a first N-type impurity) doped over a portion of the P-type impurity302on the first substrate300, according to an embodiment of the present disclosure. The N-type impurity306is disposed over a portion of an upper surface308of the P-type impurity302.

FIG. 9illustrates a cross-sectional view of a P-type impurity310(for example, a second P-type impurity) doped over a portion of the N-type impurity306that is doped over the P-type impurity302on the first substrate300, according to an embodiment of the present disclosure. The first substrate300is doped with the P-type impurity302, the N-type impurity306, and the P-type impurity310to define junctions of the diode148, which may be a p-n junction diode.

FIG. 10illustrates a cross-sectional view of a passivation layer312deposited over the first substrate300, according to an embodiment of the present disclosure. In particular, the passivation layer312is deposited over the P-type impurity302, the N-type impurity306, the P-type impurity310such that channels313and314are formed for the diode148.

FIG. 11illustrates a cross-sectional view of a first metal layer316that forms electronic contacts318and320deposited over the passivation layer312, according to an embodiment of the present disclosure. The passivation layer312provides electrode pads for junctions of diode148.

FIG. 12illustrates a cross-sectional view of a second metal layer322that forms a microstrip feed network324deposited over the first metal layer316, according to an embodiment of the present disclosure.FIG. 13illustrates a cross-sectional view of a third metal layer326that forms a backside ground plane328, such as a backside ground plane, deposited on the first substrate300opposite from the second metal layer322, according to an embodiment of the present disclosure.

FIG. 14illustrates a cross-sectional view of a fourth metal layer330that forms the antenna arrays (such as the transmit antenna array144and the first receive antenna array140) deposited on a second substrate332, according to an embodiment of the present disclosure.FIG. 15illustrates a cross-sectional view of the cavity174, vent channel176, and vent outlet182formed (such as via laser etching) in the second substrate332, according to an embodiment of the present disclosure.FIG. 16illustrates a cross-sectional view of the first substrate300bonded to the second substrate332to form the pressure sensor assembly120shown through line16-16ofFIG. 5, according to an embodiment of the present disclosure.

Referring toFIGS. 5-16, the pressure sensor assembly120includes the transmit antenna array144, the first receive antenna array140, and the second receive antenna array142disposed on the second (or optionally, first) substrate332, an electronics layer including the microstrip feed network324, and the diode148underneath the second substrate332, and disposed on the first (or optionally, second) substrate300. Accordingly, the transmit antenna array144, the first receive antenna array140, and the second receive antenna array142are electrically connected together by the microstrip feed network324which is underneath the top surface of the pressure sensor assembly120. The microstrip feed network324and the diode148are electrically connected and may be embedded within the pressure sensor assembly120, such as between the first substrate300and the second substrate332.

FIG. 17illustrates a perspective top view of the pressure sensor assembly120, according to an embodiment of the present disclosure. The pressure sensor assembly120shown inFIG. 17is similar to the pressure sensor assembly120shown inFIG. 5, except that a cavity400, which enhances bandwidth, is formed underneath at least a portion of the transmit antenna array144. A cavity may also be formed underneath at least a portion of one or both of the first receive antenna array140and/or the second receive antenna array142. The cavity400may be formed underneath the transmit antenna array144in the substrate300or the substrate332, shown inFIG. 16.

FIG. 18illustrates a cross-sectional view of the cavity400formed in the first substrate300, according to an embodiment of the present disclosure. Referring toFIGS. 17-18, the pressure sensor assembly120is initially formed as described with respect toFIGS. 6-13. Then, the cavity400is formed in the first substrate300, such as through laser etching. Next, the first receive antenna array140, the second receive antenna array142, the transmit antenna array144, the cavity174, the vent channel176, and the vent outlet182are formed in relation to the second substrate332as shown and described with respect toFIGS. 14 and 15.

FIG. 19illustrates a cross-sectional view of the first substrate300bonded to the second substrate332to form the pressure sensor assembly120shown through line19-19ofFIG. 17. It has been found that the cavity400underneath the transmit antenna array144increases gain and bandwidth of the transmit antenna array144. The cavity400may be formed within the substrate300, as shown, or the substrate332. Any of the embodiments of the present disclosure may include the cavity400underneath the transmit antenna array144.

FIG. 20illustrates a perspective top view of the pressure sensor assembly120, according to an embodiment of the present disclosure. The pressure sensor assembly120shown and described with respect toFIG. 20is similar to the pressure sensor assembly120shown and described with respect toFIGS. 2-4, except that a cavity500is formed underneath at least a portion of the transmit antenna array144. A cavity may also be formed underneath at least a portion of one or both of the first receive antenna array140and/or the second receive antenna array142.

In order to form the pressure sensor assembly120, an N-type impurity502is doped on a P-type impurity504that is doped on a first substrate506, as shown inFIG. 21. Next, as shown inFIG. 22, a P-type impurity508is doped on the N-type impurity502that is doped on the P-type impurity504that is doped on the first substrate506to form the junctions of the diode148, such as a p-n junction diode. Next, as shown inFIG. 23, a passivation layer510is deposited over the first substrate506. As shown inFIG. 24, a first metal layer512is then deposited over the passivation layer510to form electronics contacts514. Then, as shown inFIG. 25, a second metal layer516is deposited over the first substrate506to form antenna arrays (such as the arrays140,142, and144shown inFIG. 20). Next, the first cavity174, the vent channel176, and the vent outlet182formed in the first substrate506, such as through laser etching. Next, as shown inFIG. 27, a third metal layer520deposited on a second substrate522to form a backside ground plane. As shown inFIG. 28, the cavity500(for example, a second cavity), which enhances bandwidth, is formed in the second substrate522, such as via laser etching. As shown inFIG. 29, the first substrate506is bonded to the second substrate522to form the pressure sensor assembly120shown through line29-29ofFIG. 20. The first receive antenna array140, the second receive antenna array142, and the transmit antenna array144may be edge feed antenna arrays. It has been found that the cavity500underneath the transmit antenna array144increases gain and bandwidth of the transmit antenna array144. The cavity500may be formed within the first substrate506, as shown, or the second substrate522(or any of the substrates described herein). Any of the embodiments of the present disclosure may include the cavity500underneath the transmit antenna array144.

FIG. 30Aillustrates a flow chart of a pressure sensing method, according to an embodiment of the present disclosure. The pressure sensing method includes providing (550) a first receive antenna array that receives a first signal at a first frequency, providing (552) a second receive antenna array that receives a second signal at a second frequency that differs from the first frequency, coupling (for example, electrically connecting) (554) a diode to the first receive antenna array and the second receive antenna array, coupling (for example, electrically connecting) (556) a transmit antenna array to the diode, receiving (558), by the diode, the first signal at the first frequency and the second signal at the second frequency, outputting (560), by the diode, a third signal at a third frequency that is a difference between the first frequency and the second frequency, receiving (562), by the transmit antenna array from the diode, the third signal at the third frequency, and outputting (564), by the transmit antenna array, the third signal at the third frequency. In at least one embodiment, the outputting (564), by the transmit antenna array, includes outputting the third signal at the third frequency to a receiver, and wherein the pressure sensing method further includes determining, by the receiver, a pressure level from the third signal at the third frequency.

FIG. 30Billustrates a flow chart of a method of forming a pressure sensor assembly, according to an embodiment of the present disclosure. In at least one embodiment, the method of forming includes providing (580) a first substrate that is a P-type doped semiconductor substrate, doping (582) a first N-type impurity on the first substrate, doping (584) a second N-type impurity on the first N-type impurity to form, at least in part, a diode, depositing (586) an oxidation layer over the first substrate, depositing (588) a metal over the oxidation layer to form a first receive antenna array, a second receive antenna array, a first microstrip feed, a second microstrip feed, a transmit antenna array, and electrical contacts, forming (590) (such as through laser etching) a first cavity, a vent channel, and a vent outlet into the first substrate, depositing (592) a backside ground plane onto a second substrate, and bonding (594) the second substrate to the first substrate. It is to be understood that the method shown inFIG. 30Bis merely exemplary. The method of forming the pressure sensor assembly may include more or less steps than shown.

FIG. 30Cillustrates a flow chart of a method of forming a pressure sensor assembly, according to an embodiment of the present disclosure. In at least one embodiment, the method includes providing (600) a first substrate that is an intrinsic semiconducting substrate, doping (602) the first substrate with a first P-type impurity, doping (604) a first N-type impurity over a portion of the first P-type impurity on the first substrate, doping (606) a second P-type impurity over a portion of the first N-type impurity to define, at least in part, a diode, depositing (608) a passivation layer over the first substrate, depositing (610) a first metal layer over the passivation layer to form electronic contacts, depositing (612) a second metal layer over the first metal layer to form a microstrip feed network, depositing (614) a third metal layer on the first substrate opposite from the second metal layer to form a backside ground plane, depositing (616) a fourth metal layer on a second substrate to form a first receive antenna array, a second receive antenna array, and a transmit antenna array, forming (618) at least one cavity in the first substrate or the second substrate, and bonding (620) the first substrate to the second substrate. It is to be understood that the method shown inFIG. 30Cis merely exemplary. The method of forming the pressure sensor assembly may include more or less steps than shown.

FIG. 31illustrates a perspective front view of an aircraft700. Embodiments of the present disclosure may be used to detect noise is sound pressure levels generated by portion of the aircraft700. For example, any of the pressure sensor assemblies120described herein may be used to detect noise is sound pressure levels generated by engines of the aircraft700.

The aircraft700may include a propulsion system that may include two engines712, for example. Optionally, the propulsion system may include more engines712than shown. The engines712are carried by wings716of the aircraft700. In other embodiments, the engines712may be carried by a fuselage718and/or an empennage720. The empennage720may also support horizontal stabilizers722and a vertical stabilizer724. The wings716, the horizontal stabilizers722, and the vertical stabilizer724may each include one or more control surfaces.

Optionally, embodiments of the present disclosure may be used with respect to various other structures, such as other vehicles (including automobiles, watercraft, spacecraft, and the like), buildings, appliances, and the like.

FIG. 32illustrates a front view of an engine800, according to an embodiment of the present disclosure. The engines712shown and described with respect toFIG. 31are examples of the engine800shown inFIG. 32.

The engine800includes a housing802and an engine core804retained within the housing802. Fan blades806are coupled to the engine core804. The fan blades806rotate about a central axis808of the engine core804.

The pressure sensing system100is coupled to the engine800. For example, the engine800includes the pressure sensing system100, or at least portions thereof. The pressure sensing system100is configured to detect pressure in relation to the engine800, such as pressure generated within the engine800.

As shown, a pressure sensor assembly120, such as an RFID sensor tag, is coupled to a fan blade806. As an example, the pressure sensor assembly120is mounted to an exterior or interior surface of the fan blade806. As another example, the pressure sensor assembly120is embedded within the fan blade806. The fan blade806is an example of the component122shown inFIG. 1. Additional pressure sensor assemblies120can be coupled to additional fan blades806.

One or more waveguides810extend into and through the housing802. For example, the housing802can include channels into which the waveguides810are received and retained. As shown, the housing802can includes a plurality of waveguides810. In at least one embodiment, the housing802includes one waveguide810.

The waveguide810is coupled to the transceiver assembly102. In at least one embodiment, the waveguide810includes the transceiver assembly102. In at least one other embodiment, the transceiver assembly102includes the waveguide810. As another example, a first waveguide810aincludes the transmit antenna array106, or vice versa, a second waveguide810bincludes the transmit antenna array108, or vice versa, and a third waveguide810cincludes the receive antenna array110, or vice versa. For example, the first waveguide810aand the second waveguide810btransmit the first signal128and the second signal130, respectively, (such as electromagnetic plane waves), and the third waveguide810creceives the third signal132(such as an electromagnetic plane wave). Optionally, the transmit antenna array106, the transmit antenna array108, and the receive antenna array110can be coupled to (such as within) a common waveguide810. As another example, the transmit antenna array106and the transmit antenna array108are coupled to a first waveguide810, and the receive antenna array110is coupled to a second waveguide810that differs from the first waveguide810.

Referring toFIGS. 1 and 32, the first signal128and the second signal130are transmitted by the transceiver assembly102through the waveguide(s)810(such as the waveguides810aand810b) into an interior chamber812of the engine800, such as toward the fan blades806. Further, the third signal132is received by the transceiver assembly102from the pressure sensor assembly120coupled to the fan blade806through the waveguide810(such as the waveguide810c).

As described, the transmit antenna array106, the transmit antenna array108, and the receive antenna array110are secured within one or more waveguides810. Alternatively, the engine800may not include the waveguide(s)810. Instead, the transceiver assembly102can be secured within the interior chamber812of the engine800.

FIG. 33illustrates a perspective lateral view of the waveguide810, according to an embodiment of the present disclosure. In at least one embodiment, the waveguide810includes a tube814defining a central channel816. The waveguide810may be formed of aluminum or another conductive material. The waveguide810can includes a circular or elliptical axial cross-section. As another example, the waveguide810can include a rectangular-shaped or square-shaped axial cross-section.

Referring toFIGS. 1, 32, and 33, the transceiver assembly102transmits the first signals128and130into a central channel816. Further, the transceiver assembly102receives the third signal132from the pressure sensor assembly120through a central channel816.

During operation, the fan blades806rotate within the housing802. The pressure sensor assembly120is visible to the waveguide(s)810(and therefore the transceiver assembly102) for a fraction of each full revolution of the fan blade806to which the pressure sensor assembly120is mounted.

FIG. 34illustrates a pulse wave related to revolution of a fan blade having a pressure sensor assembly, according to an embodiment of the present disclosure. As noted, the pressure sensor assembly120is able to communicate with the transceiver assembly102for a fraction of each blade revolution. In particular, trrepresents a pulse of time in which the transceiver assembly102can transmit signals to, and receive signals from, the pressure sensor assembly120coupled to the fan blade806(shown inFIGS. 1 and 32). A full revolution of the fan blade806is represented by tb.

FIG. 35illustrates a relationship between the fan blade806having the pressure sensor assembly120and the waveguide810, according to an embodiment of the present disclosure. The transceiver assembly102is coupled to the waveguide810. For example, the transceiver assembly102, or portions thereof, are disposed within the waveguide810.

ParameterExpressionUnitsField of view of sensorθsdeg.Turbine speedω = 2πfrad/sBlade revolution timetb= 1/fsWaveguide to sensor distanced1in.Waveguide to axle distanced2in.Equivalent angle from axleθ∝tan-1⁢d1⁢tan⁢⁢θsd2deg.Max. measurable acoustic bandwidthfa∝1tb⁢θHz
Referring to the chart above andFIG. 35, the maximum measurable acoustic bandwidth is inversely proportional to blade revolution time and field of view818of the pressure sensor assembly120.

Referring toFIGS. 1 and 32, in an exemplary embodiment, the transmitter112provides a first time-varying power signal to the first transmit antenna array106, which in response, transmits a first signal128(such as a first RF signal) at a first frequency. For example, a first time-varying electric field is generated by transducing a first time-varying electrical power signal using a first electromagnetic waveguide, such as a first waveguide810or antenna. The first time-varying electric field is then incident on the pressure sensor assembly120, where a first time-varying current signal is generated.

Similarly, the transmitter112provides a second time-varying power signal to the second transmit antenna array108, which in response, transmits a second signal130(such as a second RF signal) at a second frequency that differs from the first frequency. For example, a second time-varying electric field is generated by transducing a second time-varying electrical power signal using a second electromagnetic waveguide, such as a second waveguide810or antenna. The second time-varying electric field is then incident on the pressure sensor assembly120, where a second time-varying current signal is generated.

Within the pressure sensor assembly120, the first time-varying current signal is modulated by an acousto-mechanical transducer, which is simultaneously excited by a time-varying pressure field. The first time-varying current signal is then modulated with the second time-varying current signal, thereby resulting in a third time-varying current signal. A third time-varying electric field is then generated by the third time-varying current signal. A third time-varying electrical power signal is generated at the transceiver assembly102by a third electromagnetic waveguide810. In at least one embodiment, the pressure determination control unit115evaluates the magnitude and/or phase of the electrical power signals to determine the time-varying pressure.

Alternatively, in another embodiment, a first time-varying electric field is generated by transducing a first time-varying electrical power signal using a first electromagnetic waveguide. The first time-varying electric field is incident on the pressure sensor assembly120, where a first time-varying current signal is generated. The first time-varying current signal is modulated by an acousto-mechanical transducer, which is simultaneously excited by a time-varying pressure field. The first time-varying current signal is further modulated, resulting in a second time-varying current signal. A second time-varying electric field is then generated by the second time-varying current signal. A second time-varying electrical power signal is generated at the transceiver assembly102by transducing the second time-varying electric field using a second electromagnetic waveguide. The pressure determination control unit115may then evaluate the magnitude and/or phase of the electrical power signals to determine the time-varying pressure.

FIG. 36illustrates a flow chart of a pressure sensing method for an engine of an aircraft, according to an embodiment of the present disclosure. The pressure sensing method includes coupling (900) a transceiver assembly to a portion of the engine; coupling (902) a pressure sensor assembly to a fan blade of the engine; transmitting (904), from the transceiver assembly, a first signal at a first frequency and a second signal at a second frequency that differs from the first frequency; receiving (906), by the pressure sensor assembly, the first signal and the second signal; transmitting (908), by the pressure sensor assembly, a third signal at a third frequency that is a difference between the first frequency of the first signal and the second frequency of the second signal; receiving (910), by the transceiver assembly, the third signal at the third frequency; and determining (912) the pressure in relation to the engine based on the third signal. In at least one embodiment, said determining includes determining, by a pressure determination control unit, the pressure by analyzing the third signal.

As described herein, embodiments of the present disclosure provide efficient systems and methods for detecting pressure, such as within an engine of an aircraft. Further, embodiments of the present disclosure provide compact and cost-effective pressure sensor assemblies.