Electromagnetic shielded testing chamber with ventilation

A testing apparatus for electromagnetically sensitive equipment includes a housing defining a testing chamber. The housing blocks transmission of electromagnetic waves from an external environment into the testing chamber and reduces reflection of electromagnetic waves within the testing chamber. The testing apparatus also includes a tube defining an air flow path between the testing chamber and the external environment. The tube blocks transmission of electromagnetic waves from the external environment into the air flow path. The tube includes a proximal end coupled to an opening in the housing such that the air flow path is fluidly coupled to the testing chamber via the opening, a distal end opposing the proximal end, and a bent segment extending between the proximal end and the distal end.

BACKGROUND

The present disclosure generally relates to a testing apparatus for electromagnetically sensitive equipment, and more specifically to an air flow assembly of the testing apparatus.

Electronic devices, such as laptops, mobile phones, televisions, smart watches, AM/FM radios, and the like, include various components, such as transceivers, transmitters, receivers, and antennas, to wirelessly transmit and/or receive communications via electromagnetic waves, such as radio waves. These components, referred to in certain instances of the present disclosure as electromagnetically sensitive equipment, may be tuned or otherwise configured to convert between electrical data signals and electromagnetic waves. In order to ensure adequate performance of the electromagnetically sensitive equipment, a testing apparatus defining a testing chamber may be employed to test various performance metrics of the electromagnetically sensitive equipment. However, conventional testing apparatuses may include or be employed in relatively uncontrolled environments. For example, conventional testing apparatuses may include poor temperature control of the testing chamber in which the electromagnetically sensitive equipment is disposed for testing. Further, conventional testing apparatuses may include poor shielding of the testing chamber from transmission of electromagnetic waves into the testing chamber from an external environment, and poor electromagnetic anti-reflective properties that enable undesirable reflection of electromagnetic waves from internal surfaces of the testing apparatus toward the electromagnetically sensitive equipment. The relatively uncontrolled environment of conventional testing apparatuses may lead to inaccurate test results, imprecise tuning of the electromagnetically sensitive equipment, and inadequate performance of the electromagnetically sensitive equipment and corresponding electronic devices. Accordingly, it is now recognized that an improved testing apparatus for testing electromagnetically sensitive equipment is desired.

SUMMARY

In one embodiment, a testing apparatus for electromagnetically sensitive equipment includes a housing defining a testing chamber. The housing is configured to block transmission of electromagnetic waves from an external environment into the testing chamber and to reduce reflection of electromagnetic waves within the testing chamber. The testing apparatus also includes a tube defining an air flow path between the testing chamber and the external environment. The tube is configured to block transmission of electromagnetic waves from the external environment into the air flow path. The tube includes a proximal end coupled to an opening in the housing such that the air flow path is fluidly coupled to the testing chamber via the opening, a distal end opposing the proximal end, and a bent segment extending between the proximal end and the distal end.

In another embodiment, a testing apparatus for electromagnetically sensitive equipment includes a housing defining a testing chamber configured to receive the electromagnetically sensitive equipment. The testing apparatus also includes an air flow assembly having a proximal end coupled to the housing and a tube extending between the proximal end and a distal end of the air flow assembly. The tube defines an air flow channel between the testing chamber and an environment external to the testing apparatus. The tube includes a bent segment extending between the proximal end of the air flow assembly and the distal end of the air flow assembly. The testing apparatus also includes an electromagnetic barrier defined about the testing chamber by a first conductive material of the housing and a second conductive material of the air flow assembly.

In yet another embodiment, an air flow assembly for an electromagnetic wave testing apparatus includes a first end configured to be coupled to a housing of the electromagnetic wave testing apparatus and including a first conductive material, a second end opposing the first end and including a second conductive material, and an air flow tube extending from the first end to the second end and including a third conductive material. The air flow tube defines a 45-135 degree bend between the first end and the second end.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Use of the term “approximately,” “near,” “about”, “close to,” and/or “substantially” should be understood to mean including close to a target (e.g., design, value, amount), such as within a margin of any suitable or contemplatable error (e.g., within 0.1% of a target, within 1% of a target, within 5% of a target, within 10% of a target, within 25% of a target, and so on). Moreover, it should be understood that any exact values, numbers, measurements, and so on, provided herein, are contemplated to include approximations (e.g., within a margin of suitable or contemplatable error) of the exact values, numbers, measurements, and so on.

The disclosure is directed to a testing apparatus for electromagnetically sensitive equipment, and more specifically to air flow assemblies of the testing apparatus. For example, electromagnetically sensitive equipment that facilitates wireless communication via electromagnetic waves (e.g., radio waves) may be employed in a variety of electronic devices, such as a laptop, a mobile phone, a television, a smart watch, an AM/FM radio, or the like. The electromagnetically sensitive equipment employed in these electronic devices may include transceivers, transmitters, receivers, and/or antennas. In order to ensure adequate performance of the electromagnetically sensitive equipment, a testing apparatus defining a testing chamber may be employed to test or measure various performance metrics of the electromagnetically sensitive equipment disposed within the testing chamber. Based at least in part on the test results, the electromagnetically sensitive equipment may be tuned or otherwise configured for desired performance in the electronic devices employing the electromagnetically sensitive equipment.

In accordance with the present disclosure, the testing apparatus may include a housing defining the testing chamber that receives the electromagnetically sensitive equipment (e.g., a transceiver, a transmitter, a receiver, and/or an antenna) and/or devices having the electromagnetically sensitive equipment. In general, aspects of the testing apparatus, including the housing and air flow assemblies used to control a temperature of the testing chamber, may define an electromagnetic barrier (e.g., a Faraday cage) about the testing chamber. For example, the housing and the air flow assemblies may include a material, such as a conductive material, that surrounds the testing chamber and generates the electromagnetic barrier (e.g., the Faraday cage) about the testing chamber. It should be noted that the conductive material may be employed as a mesh or a screen in certain portions of the testing apparatus, such as in waveguides associated with the air flow assemblies of the testing apparatus, while still maintaining the electromagnetic barrier about the testing chamber. In general, the electromagnetic barrier may block electromagnetic waves in an environment surrounding the testing apparatus (e.g., external to the testing apparatus) from being transmitted through the testing apparatus and into the testing chamber.

The testing chamber, isolated from electromagnetic waves outside of the testing apparatus as described above, may also be protected from electromagnetic interference associated with reflection of electromagnetic waves propagated by the electromagnetically sensitive equipment within the testing chamber. For example, aspects of the testing apparatus, including the housing and the air flow assemblies, may include electromagnetic anti-reflective properties that reduce or negate reflection of electromagnetic waves (or effects thereof) from internal surfaces of the testing apparatus and directed back toward the electromagnetically sensitive equipment within the testing chamber. That is, certain inner surfaces of the testing apparatus, including the inner surfaces of the housing and/or the inner surfaces of the air flow assemblies, may be defined by (or include) electromagnetic absorbing material, such as a dielectric polyurethane material, that may attenuate or reduce an intensity of electromagnetic waves that contact the electromagnetic absorbing material.

The above-described air flow assemblies may be coupled to the housing of the testing apparatus about corresponding openings in the housing, such that air flow channels of the air flow assemblies are fluidly coupled to the testing chamber defined by the housing. In general, the air flow assemblies may be employed to control a temperature of the testing chamber. One of the air flow assemblies may enable an air flow from the environment surrounding the testing apparatus into the testing chamber. The other of the air flow assemblies may enable an air flow from the testing chamber to the environment surrounding the testing apparatus.

One or both of the air flow assemblies may include a fan that generates the above-described air flows. A thermostat associated with the testing apparatus may receive sensor feedback indicative of a temperature of the testing chamber and control the one or more fans based on the sensor feedback. For example, in certain operating conditions, the sensor feedback may indicate that the temperature of the testing chamber is higher than a threshold temperature. The thermostat may activate the one or more fans of the air flow assemblies in response to the temperature of the testing chamber being higher than the threshold temperature. The air flows into and out of the testing chamber, enabled by the air flow assemblies and corresponding fan(s) activated by the thermostat, and may reduce the temperature of the testing chamber. The thermostat may deactivate the fan(s) in response to the temperature of the testing chamber being reduced below the threshold temperature.

While the air flow assemblies may include inner surfaces defined by electromagnetic absorbing material that may attenuate electromagnetic waves, the air flow assemblies may additionally or alternatively include a geometry that reduces or negates electromagnetic interference otherwise caused by electromagnetic waves reflected from the inner surfaces of the testing apparatus. For example, each air flow assembly may include a proximal end coupled to the housing about a corresponding opening in the housing, a distal end opposing the proximal end, and a tube extending from the proximal end to the distal end. An inner surface extending from the proximal end, through the tube, and to the distal end of the air flow assembly may define an air flow path between the testing chamber and the environment surrounding the testing apparatus. The tube may include a bend, referred to in certain instances of the present disclosure as a bent segment. The bent segment may cause electromagnetic waves contacting a first portion of the inner surface of the air flow assembly at the bent segment to reflect in a preferred direction or at a preferred angle toward a second portion of the inner surface of the air flow assembly.

Multiple contacts between the electromagnetic wave and the inner surface of the air flow assembly may improve attenuation of the electromagnetic wave, thereby decreasing or negating undesirable effects of electromagnetic waves reflected back toward the electromagnetically sensitive equipment disposed in the testing chamber. As previously described, each air flow assembly may include a waveguide forming a mesh or screen via a material, such as a conductive material, that enables an air flow therethrough while maintaining the electromagnetic barrier about the testing chamber. The waveguide may be disposed, for example, in the distal end of the air flow assembly. In some embodiments, the fan(s) of the air flow assemblies are disposed adjacent to, or extend into, the waveguides of the air flow assemblies.

The above-described testing apparatus, described in more detail below with reference to the drawings, facilitates a more controlled environment of the corresponding testing chamber relative to conventional systems. For example, the presently disclosed testing apparatus may reduce or negate transmission of electromagnetic waves through the testing apparatus and into the testing chamber, reduce or negate undesirable reflection of electromagnetic waves within the testing chamber, and/or improve temperature control of the testing chamber over conventional systems. These and other features are described in detail below with reference to the drawings.

FIG.1is a perspective view of an embodiment of a testing apparatus10for testing electromagnetically sensitive equipment. The testing apparatus10may include a testing chamber12that receives the electromagnetically sensitive equipment. The electromagnetically sensitive equipment may include, for example, a transceiver, a transmitter, a receiver, and/or an antenna, or any device having these components, utilized to wirelessly transmit and/or receive communications via electromagnetic waves, such as radio waves. For example, the electromagnetically sensitive equipment may be used in a variety of electronic communication devices, such as laptops, mobile phones, televisions, AM/FM radios, smart watches, and the like.

Tests conducted via the testing apparatus10may be performed to tune or otherwise configure the electromagnetically sensitive equipment for, for example, appropriately converting between electrical data signals and electromagnetic signals, such as radio frequency signals. In order to test the electromagnetically sensitive equipment in a controlled environment, the testing apparatus10may include various features described in detail below that control a temperature of the testing chamber12and/or isolate the testing chamber12and the electromagnetically sensitive equipment within the testing chamber12from various types of electromagnetic interference. The controlled environment associated with embodiments of the present disclosure may improve accuracy and precision of the tests conducted on the electromagnetically sensitive equipment.

In the illustrated embodiment, the testing apparatus10includes a housing14defining the testing chamber12in which the electromagnetically sensitive equipment is disposed for testing. The housing14may include, for example, a body16and a lid18that may be coupled to the body16to generally enclose the testing chamber12. The housing14, along with other components of the testing apparatus10, may block transmission of electromagnetic waves from an external environment20into the testing chamber12. In particular, the housing14may include a material, such as a conductive material, that forms a portion of an electromagnetic barrier (e.g., Faraday cage) about the testing chamber12. Other portions of the testing apparatus10that form other portions of the electromagnetic barrier will be described in detail below.

In addition to forming a portion of the above-described electromagnetic barrier, the housing14may include electromagnetic anti-reflective properties. For example, inner surfaces22of the housing14may be defined by (or include) an electromagnetic absorbing material that attenuates or reduces an intensity of electromagnetic waves emitted by the electromagnetically sensitive equipment and contacting the electromagnetic absorbing material. The electromagnetic absorbing material may include, for example, a dielectric material, such as a dielectric polyurethane material. An example of a dielectric polyurethane material that may define the inner surfaces22of the housing14is Eccosorb® AN-79. In some embodiments, the electromagnetic absorbing material may include a foam consistency (e.g., a dielectric polyurethane foam material). In general, the electromagnetic absorbing material may attenuate or reduce an intensity of an electromagnetic wave that contacts the electromagnetic absorbing material by 20-50 decibels.

The testing apparatus10in the illustrated embodiment also includes features that promote air flows through the testing chamber12. Indeed, the electromagnetically sensitive equipment tested via the testing apparatus10may be temperature-sensitive. Thus, air flow features of the testing apparatus10may be employed to reduce undesirably high temperatures within the testing chamber12. In the illustrated embodiment, the testing apparatus10includes a first air flow assembly24disposed adjacent to a base26of the testing apparatus10, where the base26is coupled to (or defines a portion of) the body16of the housing14of the testing apparatus10. In some embodiments, wheels27of the testing apparatus10may be coupled to the base26to enable rolling mobility of the testing apparatus10.

Further, the testing apparatus10may include a second air flow assembly28disposed adjacent to a top30of the body16of the housing14, where the top30may include a highest point or edge of the body16of the housing14relative to a height direction (e.g., y-axis). The lid18of the housing14may be coupled to the top30of the body16of the housing14when the testing apparatus10is in an operational state. The first air flow assembly24may facilitate an air flow from the external environment20into the testing chamber12, whereas the second air flow assembly28may facilitate an air flow from the testing chamber12to the external environment20. Locations of the first air flow assembly24and the second air flow assembly28relative to the housing14may differ in other embodiments.

In general, the first air flow assembly24, the second air flow assembly28, or both may include a fan that biases air flows from the external environment20, through the first air flow assembly24, into and through the testing chamber12, through the second air flow assembly28, and to the external environment20. The fan(s) may be controlled via a thermostat32that receives, from a sensor34(e.g., a temperature sensor, such as a thermocouple), sensor feedback indicative of a temperature within the testing chamber12. For example, the thermostat32may determine whether the sensor feedback indicates that the temperature within the testing chamber12is above a threshold temperature. In response to the temperature within the testing chamber12being above the threshold temperature, the thermostat32may activate the fan(s) associated with the first air flow assembly24and/or the second air flow assembly28to bias air flows into and out of the testing chamber12, as described above. As noted above, the second air flow assembly28may output an air flow into the external environment20and the first air flow assembly24may receive an air flow from the external environment20. Accordingly, cool air from the external environment20may be biased into a lower portion of the testing chamber12and warm air in the testing chamber12may be biased out of an upper portion of the testing chamber12. The relative positions of the first air flow assembly24and the second air flow assembly28illustrated inFIG.1and described above may improve a cooling efficiency of the testing apparatus10.

Like the housing14of the testing apparatus10, the first air flow assembly24and the second air flow assembly28may include a material, such as a conductive material, that forms a portion of the electromagnetic barrier defined by the testing apparatus10about the testing chamber12. Thus, electromagnetic waves propagating in the external environment20may be blocked from passing into the testing chamber12through the housing14, the first air flow assembly24, and the second air flow assembly28. It should be noted that the conductive material of the housing14, the first air flow assembly24, and the second air flow assembly28may be different types of conductive materials, or the conductive material of the housing14, the first air flow assembly24, and the second air flow assembly28may be the same. Further, each of the housing14, the first air flow assembly24, and the second air flow assembly28may include multiple types of conductive materials (e.g., the housing14may include a first conductive material and a second conductive material different than the first conductive material). The conductive material or materials may include, for example, aluminum, copper, stainless steel, or some other conductive material. As will be appreciated in view of later drawings, each of the first air flow assembly24and the second air flow assembly28may include a waveguide that blocks transmission of electromagnetic waves into the air flow assemblies24,28while enabling air to pass through the waveguides and between the testing chamber12and the external environment20. For example, the waveguide may be a mesh or a screen formed by a conductive material that enables an airflow through the waveguide and blocks transmission of electromagnetic waves in the external environment20through the waveguide.

The first air flow assembly24and the second air flow assembly28may also include electromagnetic anti-reflective properties. For example, the first air flow assembly24and the second air flow assembly28may include inner surfaces defined by (or including) electromagnetic absorbing material the same as, or similar to, the electromagnetic absorbing material defining the inner surfaces22of the housing14described above. Additionally or alternatively, the first air flow assembly24and the second air flow assembly28may include geometries that reduce or negate reflection of electromagnetic waves back toward the electromagnetically sensitive equipment disposed in the testing chamber12. For example, as shown in the illustrated embodiment, each of the first air flow assembly24and the second air flow assembly28may include a bent segment. The bent segment may cause an unabsorbed or under-absorbed electromagnetic wave contacting a first portion of an inner surface of the bent segment to reflect in a preferred direction or at a preferred angle toward and into a second portion of the inner surface, as opposed to being reflected directly back toward the electromagnetically sensitive equipment in the testing chamber12.

In some instances, the unabsorbed or under-absorbed electromagnetic wave may contact the inner surface of the first air flow assembly24or the second air flow assembly28multiple (e.g., three, four, or more) times. An intensity of the unabsorbed or under-absorbed electromagnetic wave may be reduced with each instance of the unabsorbed or under-absorbed electromagnetic wave contacting the inner surface. Thus, the bent segment for each of the first air flow assembly24and the second air flow assembly28may increase a number of instances electromagnetic waves contact the inner surface of the corresponding air flow assembly24,28, thereby increasing an attenuation of the electromagnetic waves.

The above-described features, including the electromagnetic barrier, the electromagnetic anti-reflective properties, and the air flow assemblies24,28, may improve accuracy and precision of tests conducted for electromagnetically sensitive equipment via the testing apparatus10. More detailed aspects of the testing apparatus10and corresponding air flow assemblies24,28will be provided below with reference to later drawings.

FIG.2is a cross-sectional view of an embodiment of the testing apparatus10ofFIG.1. Electromagnetically sensitive equipment33may be disposed in the testing chamber12defined by the testing apparatus10. The electromagnetically sensitive equipment33may include a first unit35and a second unit36, where the first unit35is tested by the second unit36. In some embodiments, the second unit36may be integrated with the testing apparatus10(e.g., integrated with the housing14of the testing apparatus10), as opposed to being separate from the testing apparatus10and disposed in the testing chamber12. In the illustrated embodiment, the first unit35being tested includes a transmitter37and/or a receiver38, and one or more antennas39. The transmitter37and the receiver38may be collectively referred to as a transceiver. The transmitter37of the first unit35may emit an electromagnetic signal (e.g., via the one or more antennas39) and aspects of the electromagnetic signal (e.g., a strength, intensity, quality, and so on, of the electromagnetic signal) may be measured by the second unit36and recorded and/or analyzed. Additionally or alternatively, the receiver38of the first unit35may receive an electromagnetic signal (e.g., via the one or more antennas39and from the second unit36), and aspects of the electromagnetic signal, or derivatives thereof (e.g., aspects of an electrical signal generated from the electromagnetic signal received at the first unit35), may be recorded and/or analyzed. The above-described examples are provided for context and are not limiting on the types of electromagnetic testing that can be conducted via the disclosed testing apparatus10.

In the illustrated embodiment, the testing apparatus10includes the first air flow assembly24disposed adjacent to the base26of the testing apparatus10and the second air flow assembly28disposed adjacent to the top30of the body16of the housing14of the testing apparatus10. The first air flow assembly24includes a mounting plate40coupled to the body16of the housing14of the testing apparatus10. Thus, the mounting plate40defines a proximal end42of the first air flow assembly24. The first air flow assembly24also includes a distal end44opposing the proximal end42. A waveguide46of the first air flow assembly24may be disposed at the distal end44of the first air flow assembly24. The first air flow assembly24also includes a tube48extending from the proximal end42of the first air flow assembly24to the distal end44of the first air flow assembly24(e.g., the waveguide46of the first air flow assembly24). A fan49may be disposed within an air flow channel50defined by the tube48. The fan49may bias an air flow from the external environment20surrounding the testing apparatus10, through the tube48, through an opening51in the housing14, and into the testing chamber12defined by the housing14of the testing apparatus10.

The mounting plate40, the tube48, and the waveguide46may include a material, such as a conductive material, that contributes to the electromagnetic barrier around the testing chamber12of the testing apparatus10. Of course, as previously described, the housing14of the testing apparatus10may also include the same or a similar material (e.g., conductive material) that contributes to the electromagnetic barrier around the testing chamber12of the testing apparatus10. While certain aspects of the testing apparatus10may include solid slates of the conductive material, the waveguide46of the first air flow assembly24may include a mesh or a screen formed by the conductive material. Accordingly, while the waveguide46contributes to the electromagnetic barrier formed by the testing apparatus10about the testing chamber12, the waveguide46may also enable the above-described air flow from the external environment20into the testing chamber12.

The tube48includes an inner surface58defining an air flow channel50through which the above-described air flow travels. A bent segment52of the tube48in the illustrated embodiment may cause electromagnetic waves that reach the tube48from the electromagnetically sensitive equipment33to reflect multiple times from the inner surface58, as opposed to being reflected directly back toward the electromagnetically sensitive equipment33. For example, certain electromagnetic waves generated by the electromagnetically sensitive equipment33within the testing chamber12may propagate toward the air flow channel50defined by the inner surface58of the tube48. That is, the bent segment52may cause an electromagnetic wave that contacts a first portion of the inner surface58to reflect in a preferred direction or at a preferred angle toward a second portion of the inner surface58. Moreover, each instance of the electromagnetic wave reflecting from the inner surface58of the tube48may further attenuate an intensity of the electromagnetic wave.

In some embodiments, the inner surface58may also be defined by (or include) an electromagnetic absorbing material that attenuates an intensity of the electromagnetic wave. The electromagnetic absorbing material may include, for example, a dielectric material, such as a dielectric polyurethane foam material. An example of a dielectric polyurethane material associated with the inner surface58of the tube48is Eccosorb® AN-79. As previously described, the inner surfaces22of the housing14of the testing apparatus10may include the same or similar electromagnetic absorbing material.

The second air flow assembly28may generally include the same or similar features as the first air flow assembly24, and may direct an air flow from the testing chamber12to the external environment20. For example, the second air flow assembly28may include a mounting plate60defining a proximal end62of the second air flow assembly28, a distal end64including a waveguide66of the second air flow assembly28, a tube68extending from the proximal end62to the distal end64, a fan69disposed in the tube68, an air flow channel70defined by an inner surface78of the tube68, and a bent segment72of the tube68. In some embodiments, only one of the fans49,69may be employed. For example, the first air flow assembly24may not include the fan49in certain embodiments, or the second air flow assembly28may not include the fan69in certain embodiments.

As previously described, the testing apparatus10in the illustrated embodiment includes the thermostat32that may control the fan(s)49,69. As shown, the thermostat32may be electrically coupled to the sensor34, the fan49of the first air flow assembly24, and the fan69of the second air flow assembly28via electrical wires79(e.g., extending through the housing14). In some embodiments, the fan(s)49,69may be disposed outside of the electromagnetic barrier formed by the testing apparatus10, and in such embodiments, the thermostat32may control the fan(s)49,69via wireless communication.

By including the above-referenced features, the testing apparatus10may shield the electromagnetically sensitive equipment33in the testing chamber12from undesirable electromagnetic interference while also enabling air flows through the testing chamber12and, thus, control a temperature of the testing chamber12. Detailed aspects of the air flow assemblies24,28are described in below with reference toFIGS.3-9. It should be understood thatFIGS.3-9illustrate the second air flow assembly28, but that the same or similar features may be employed at the first air flow assembly24.

FIG.3is a cross-sectional view of an embodiment of one of the air flow assemblies28for use in the testing apparatus10ofFIG.1. The air flow assembly28inFIG.3includes some of the same or similar features described above with respect toFIG.2. For example, the air flow assembly28includes the mounting plate60defining the proximal end62of the air flow assembly28, the distal end64including (or defined by) the waveguide66of the air flow assembly28, the tube68extending from the proximal end62to the distal end64, the fan69disposed in the tube68, the air flow channel70defined by the inner surface78of the tube68, and the bent segment72of the tube68.

In the illustrated embodiment, the bent segment72of the tube68includes a 90 degree bend. For example, the bent segment72may begin at a first reference plane90and end at a second reference plane92, where the first reference plane90and the second reference plane92intersect to form an angle94. In the illustrated embodiment, the angle94is 90 degrees. However, as will be appreciated with reference to later drawings and corresponding description, the angle94may be 45-135 degrees, 55-125 degrees, 65-115 degrees, 75-115 degrees, 85-95 degrees, or any other suitable angle that reduces intensity of one or more reflections of the electromagnetic wave96. As shown, the bent segment72may cause an electromagnetic wave96that enters the air flow channel70from the testing chamber12to reflect in a preferred direction or at a preferred angle that causes the electromagnetic wave96to contact the inner surface78multiple times. With each contact of the electromagnetic wave96against the inner surface78, an intensity of the electromagnetic wave96may be reduced. As previously described, the inner surface78of the tube68(and the inner surfaces22of the housing14) may be defined by (or include) an electromagnetic absorbing material (e.g., a dielectric material, a polyurethane material, etc.) that may further attenuate an intensity of the electromagnetic wave96(e.g., by 20-50 decibels).

As shown in the illustrated embodiment, the fan69of the air flow assembly28may extend into the waveguide66of the air flow assembly28. Alternatively, the fan69may be disposed between the waveguide66and the testing chamber12. The waveguide66may operate to form a portion of the electromagnetic barrier of the testing apparatus10while enabling an air flow through the air flow channel70of the air flow assembly28. For example, the waveguide66may include a mesh or a screen formed by a conductive material. Further, as shown, an end unit97of the air flow assembly28may include a width98that is greater than a width99of a portion of the tube68between the end unit97and the bent segment72of the tube68. The width98may be sized to accommodate the waveguide66and the fan69.

The air flow assembly28illustrated inFIG.3includes a single tube configuration including only one tube68. However, in certain operating conditions and/or with certain types of electromagnetically sensitive equipment being tested, the testing apparatus10may benefit from more robust temperature control, and in certain other operating conditions and/or with certain other types of electromagnetically sensitive equipment being tested, the testing apparatus10may not include any fan-induced temperature control. Accordingly, the air flow assembly28may include various configurations to enable more robust temperature control or no fan-induced temperature control.

For example,FIG.4is a perspective view of an embodiment of a single tube configuration of the air flow assembly28ofFIG.3. That is, the air flow assembly28inFIG.4includes only one instance of the tube68, and includes an opening100in the mounting plate60enclosed by a plate102. Thus, air flow through the opening100is blocked by the plate102. The plate102may include an electromagnetic absorbing material facing the testing chamber12.FIG.5is a perspective view of an embodiment of a dual tube configuration of the air flow assembly28ofFIG.3, which may provide more robust temperature control. That is,FIG.5includes two instances of the tube68coupled to the mounting plate60, where air flows are permitted through both instances of the tube68. In other words, the plate102inFIG.4may be removed from the opening100and replaced by another instance of the tube68, as illustrated inFIG.5, to generate the dual tube configuration inFIG.5. In certain embodiments, air flows through the two instances of the tube68inFIG.5may be in a common direction. For example, the air flows through the first instance of the tube68and through the second instance of the tube68may be directed toward the testing chamber12. Alternatively, the air flows through the first instance of the tube68and the second instance of the tube68may be directed away from the testing chamber12. In certain other embodiments, air flows through the two instances of the tube68inFIG.5may be in opposing directions. For example, a first air flow through the first instance of the tube68may be directed toward the testing chamber12, while a second air flow through the second instance of the tube68may be away from the testing chamber12.

FIG.6is a perspective view of an embodiment of a closed configuration of the air flow assembly28ofFIG.3, which may provide no fan-induced temperature control. That is,FIG.6includes two instances of the plate102enclosing both instances of the opening100in the mounting plate60. Both instances of the plate102may include an electromagnetic absorbing material facing the testing chamber12. As can be seen inFIGS.4-6, the same mounting plate60can be reconfigured to include the single tube configuration (e.g.,FIG.4), the dual tube configuration (e.g.,FIG.5), or the closed configuration (e.g.,FIG.6). Thus, the mounting plate60of the air flow assembly28may be reconfigured between the various configurations illustrated inFIGS.4-6while the mounting plate60is coupled to the testing apparatus10ofFIG.1.

As previously described, each tube68may include the bent segment72that increases a number of contacts between certain electromagnetic waves generated within the testing chamber12and propagated into the tube68. InFIGS.4and5, the bent segment72includes a 90 degree bend. However, the bent segment72in accordance with the present disclosure may include characteristics that differ from the characteristics illustrated inFIGS.4and5. For example,FIGS.7-9include schematic side views of various embodiments of the air flow assembly28and various characteristics of the bent segment72in accordance with the present disclosure.

FIG.7illustrates an embodiment of the air flow assembly28in which the tube68includes the bent segment72that bends more than 90 degrees (e.g., more than 110 degrees, more than 130 degrees, and so on, such as 135 degrees). For example, the bent segment72begins at the first reference plane90and ends at the second reference plane92, where the first reference plane90and the second reference plane92intersect to form the angle94and the angle94is greater than 90 degrees (e.g., more than 110 degrees, more than 130 degrees, and so on, 135 degrees).FIG.8illustrates an embodiment of the air flow assembly28in which the tube68includes the bent segment72that bends less than 90 degrees (e.g., less than 70 degrees, less than 50 degrees, and so on, such as 45 degrees). For example, the bent segment72begins at the first reference plane90and ends at the second reference plane92, where the first reference plane90and the second reference plane92intersect to form the angle94and the angle94is less than 90 degrees (e.g., less than 70 degrees, less than 50 degrees, and so on, such as 45 degrees). In general, the bent segment72may include a bend in a range of 45-135 degrees, 55-125 degrees, 65-115 degrees, 75-115 degrees, or 85-95 degrees. Additionally or alternatively, the angle94may be 45-135 degrees, 55-125 degrees, 65-115 degrees, 75-115 degrees, or 85-95 degrees.

In some embodiments, the bent segment72may include multiple bent portions and one or more inflection planes. For example,FIG.9is a schematic side view of an embodiment of the air flow assembly28in which the bent segment72of the tube68includes a first bent portion120, a second bent portion122, and an inflection plane124between the first bent portion120and the second bent portion122. The first bent portion120may extend between a first reference plane126and the inflection plane124, where the first reference plane126and the inflection plane124intersect to form a first angle128. The first angle128may be 45-135 degrees, 55-125 degrees, 65-115 degrees, 75-115 degrees, or 85-95 degrees. The second bent portion122may extend between the inflection plane124and a second reference plane130, where the inflection plane124and the second reference plane130intersect to form a second angle132. The second angle132may be 45-135 degrees, 55-125 degrees, 65-115 degrees, 75-115 degrees, or 85-95 degrees. While the first angle128and the second angle132in the illustrated embodiment are equal, in another embodiment, the first angle128and the second angle132may be different. Further, in certain embodiments, the bent segment72of the tube68may include more than two bent portions. For example, the bent segment72may include three, four, or more bent portions. In general, the embodiments illustrated inFIGS.7-9(e.g., including the various types of tubes68with various types of bent segments72) may reduce undesirable effects associated with reflection of electromagnetic waves in testing of electromagnetically sensitive equipment.

Technical effects of the present disclosure include improved temperature control and decreased electromagnetic interference associated with testing apparatuses for electromagnetically sensitive equipment.