Aerial measurement system

Abstract

The present invention provides an airborne measurement system. The measurement system includes an orthomode transducer assembly having a plurality of individually formed orthomode transducer parts forming at least two orthomode transducers. The orthomode transducer assembly has at least two output interfaces for feeding an antenna. Each of the at least two output interfaces is connected to a dedicated orthomode transducer. Two input interfaces are associated with each orthomode transducer. Each of the input interfaces is incorporated into a corresponding waveguide transition that terminates at a respective orthomode transducer associated with the corresponding input interface. The plurality of orthomode transducer parts are linearly stacked together and / or at least two output interfaces are arranged relative to each other such that the antenna phase center spacing is less than 2 cm and / or at least two output interfaces are located on a common side surface of the plane of the orthomode transducer assembly.

Description

Technical Field

[0001] The present invention relates to an over-the-air measurement system for testing a device under test. Background Art

[0002] Modern communication systems include devices for over-the-air (OTA) communication. Each device is tested against certain standards (such as 3GPP, CTIA or FTC standards) to characterize each device. Modern communication standards ensure broadband operation, but this makes it difficult to test the device under test over the entire frequency range. Typically, the test is carried out via a so-called compact antenna test range (CATR), which includes at least one reflector and an antenna facing the respective reflector, such that a beam path is established between the antenna and the device under test via the respective reflector. Thus, (indirect) far-field conditions can be provided, since the propagation distance of the electromagnetic wave is increased by the reflector located in the beam path.

[0003] Although the reflector has a sufficient operating bandwidth to test the broadband frequency range of the corresponding telecommunication standard, the limitation in the over-the-air measurement system is due to the antenna, i.e., the measurement antenna also known as the feed antenna. In fact, the antenna must have characteristics such as a stable phase center, low side lobes and a stable beam width to ensure the correct testing of the device under test. However, these requirements regarding the antenna characteristics result in a narrow-bandwidth antenna that cannot cover the entire bandwidth of the corresponding telecommunication standard for testing the device under test.

[0004] Therefore, it is known in the prior art to use a plurality of antennas assigned to different frequency ranges, wherein the plurality of antennas are mounted on an antenna positioner that moves each of the plurality of antennas to the phase center of the over-the-air measurement system, subsequently generating an optimal quiet zone. However, the additional antenna positioner increases the total cost of the measurement system and makes the entire measurement system more complex.

[0005] As an alternative solution, it is also known in the prior art to use an offset-fed antenna, wherein a second feed antenna is offset from the focus of the respective reflector, thereby generating an angled wavefront in the quiet zone. Thus, the respective quiet zones are offset from the center (off-center quiet zones), which is disadvantageous. For a measurement system with only a single reflector, an offset greater than 5 cm results in the quiet zone deviating from its center in the range of 30–100%. To compensate for this movement, it is known to move the device under test via a device under test positioner such that the device under test is repositioned at the respective center of the offset antenna. Again, an additional positioner is required, which makes the entire measurement system more costly and complex.

[0006] Therefore, there is a need for a cost-effective over-the-air measurement system that ensures broadband testing of the device under test in a less complex manner. Summary of the Invention

[0007] The present invention provides an air measurement system for testing a device under test. The air measurement system includes an orthomode transducer (OMT) assembly having a plurality of individually formed orthomode transducer parts that form at least two orthomode transducers. The orthomode transducer assembly has at least two output interfaces for feeding an antenna. Each of the at least two output interfaces is connected to a dedicated orthomode transducer. Two input interfaces are associated with each orthomode transducer. Each of the input interfaces is incorporated into a corresponding waveguide transition that terminates at the respective orthomode transducer associated with the corresponding input interface. The plurality of orthomode transducer parts are linearly stacked together.

[0008] In addition, the present invention provides an air measurement system for testing a device under test. The air measurement system includes an orthomode transducer assembly having a plurality of individually formed orthomode transducer parts that form at least two orthomode transducers. The orthomode transducer assembly has at least two output interfaces for feeding an antenna. Each of the at least two output interfaces is connected to a dedicated orthomode transducer. Two input interfaces are associated with each orthomode transducer. Each of the input interfaces is incorporated into a corresponding waveguide transition that terminates at the respective orthomode transducer associated with the corresponding input interface. At least two output interfaces are located on a common side surface of the orthomode transducer assembly, wherein the common side surface is planar.

[0009] In addition, the present invention provides an air measurement system for testing a device under test. The air measurement system includes an orthomode transducer assembly having a plurality of individually formed orthomode transducer parts that form at least two orthomode transducers. The orthomode transducer assembly has at least two output interfaces for feeding an antenna. Each of the at least two output interfaces is connected to a dedicated orthomode transducer. Two input interfaces are associated with each orthomode transducer. Each of the input interfaces is incorporated into a corresponding waveguide transition that terminates at the respective orthomode transducer associated with the corresponding input interface. The at least two output interfaces are arranged relative to each other such that the antenna phase center spacing is less than 2 cm.

[0010] Accordingly, an orthomode transducer assembly is provided having the above-described features, which relate to the structure and / or properties of the orthomode transducer assembly.

[0011] The orthogonal-mode transducer assembly provides a special offset antenna arrangement such that due to the specific design of the orthogonal-mode transducer assembly, in particular of the separately formed orthogonal-mode transducer parts that are placed and connected to each other in order to establish the orthogonal-mode transducer assembly in its assembled state, the quiet zone offset is minimized. Multiple orthogonal-mode transducer parts can be stacked linearly on top of each other, which means that multiple separately formed orthogonal-mode transducer parts are sandwiched in between, since each orthogonal-mode transducer part is assigned to a respective layer of the orthogonal-mode transducer assembly.

[0012] The respective design of the orthogonal-mode transducer assembly ensures that the antenna phase center spacing of at least two feed antennas connected to the respective output interfaces of the orthogonal-mode transducer assembly is below 2 cm, in particular below 1.8 cm. As a result, it is possible to perform broadband testing of a device under test without using a mechanical feed switch (such as an antenna positioner) or without having to reposition the device under test by means of a positioner of the device under test, thus reducing the overall cost and complexity of the airborne measurement system.

[0013] One or more respective positioners can be omitted, due to the fact that the orthogonal-mode transducer assembly is configured such that the output interfaces of the orthogonal-mode transducer assembly are located on a common side surface that is planar, such that the feed antennas connected to the output interfaces all face the same direction. In other words, the feed antennas located on the planar common side surface are located in a common plane. Furthermore, the respective output interfaces are closely positioned, thus ensuring that the feed antennas are close to each other at their respective common side surfaces. As a result, the antenna phase center spacing is significantly reduced, such that the offset of the quiet zone is minimized when changing the respective feed antennas for testing, e.g. below 2 cm, in particular below 1.8 cm.

[0014] Generally, two input interfaces are associated with each orthogonal-mode transducer and are used to forward a horizontally polarized signal and a vertically polarized signal, respectively, to a dedicated orthogonal-mode transducer that combines these two signals of different polarizations. The combined one or more signals can be forwarded to the respective output interfaces for transmission.

[0015] On the one hand, multiple orthogonal-mode transducer parts are oriented relative to each other such that two straight waveguide transitions are provided, both of which terminate at the same orthogonal-mode transducer. Thus, at least one of the multiple orthogonal-mode transducers interacts with two straight waveguide transitions for providing signals of different polarizations.

[0016] On the other hand, a plurality of orthomode transducer components are oriented relative to each other such that a straight waveguide transition and an angled waveguide transition are provided, both of which terminate at the same orthomode transducer. Thus, one of the plurality of orthomode transducers, in particular one other than the orthomode transducer interacting with the two straight waveguide transitions, interacts with the angled waveguide transition and the straight waveguide transition. Also, both waveguide transitions are used to forward horizontally polarized signals and vertically polarized signals to the corresponding orthomode transducers.

[0017] For example, the angled waveguide transition includes a portion having a ninety-degree (90°) angle. Thus, a compact and efficient waveguide transition is provided. In particular, the angled waveguide transition ensures that the plurality of orthomode transducers can be provided with signals of different polarizations while still providing a compact orthomode transducer assembly with minimized antenna phase center spacing.

[0018] According to another aspect, adjacent orthomode transducer components face each other via corresponding contact sides. The corresponding contact sides of the adjacent orthomode transducer components have structured portions that together form at least one of the orthomode transducers. Thus, the orthomode transducers of the orthomode transducer assembly, in particular each orthomode transducer, are established by two separately formed orthomode transducer components that are in contact with each other via their respective contact sides in the assembled state. In the assembled state, the contact sides face each other, where the corresponding structured portions of the contact sides are directly opposite each other, thereby forming the orthomode transducer. Thus, the orthomode transducer is provided by the corresponding structured portions that are opposite each other in the assembled state of the orthomode transducer assembly.

[0019] Furthermore, the orthomode transducer assembly can include 2×N-(N-1) separately formed orthomode transducer components, where N corresponds to the number of orthomode transducers. This particular design of the orthomode transducer assembly ensures that the number of orthomode transducer components can be significantly reduced compared to orthomode transducer assemblies known in the prior art, since at least one of the plurality of orthomode transducer components, in particular the central or intermediate orthomode transducer component, at least partially forms two orthomode transducers simultaneously. In fact, the central or intermediate orthomode transducer component, i.e., the central or intermediate orthomode transducer component having two adjacent orthomode transducer components (on opposite sides), has structured portions on opposite sides that interact with the corresponding structured portions of the adjacent orthomode transducer components located on the respective contact sides. In other words, the central or intermediate orthomode transducer component is sandwiched between two adjacent orthomode transducer components located on opposite sides.

[0020] The air measurement system further includes two feed antennas respectively connected to at least two output interfaces of the orthogonal mode transducer assembly. The corresponding feed antennas can be configured as horn antennas, which are connected to the output interfaces to receive signals provided by the corresponding orthogonal mode transducers, e.g., combined signals.

[0021] In addition, at least two waveguides can be provided, which are respectively connected to at least two input interfaces of the orthogonal mode transducer assembly. The waveguides are used to forward signals of respective polarizations to the orthogonal mode transducer assembly, e.g., signals from a signal generator of the measurement system.

[0022] The signal generator can be part of the measurement device.

[0023] The air measurement system can include at least one reflector. Thus, the air measurement system can involve a single reflector system. The reflector is used to provide (indirect) far-field conditions, as the reflector is located in the beam path established between one or more feed antennas connected to the orthogonal mode transducer assembly and the test position where the device under test is located. For example, the at least one reflector is a parabolic reflector or a non-parabolic reflector.

[0024] However, the air measurement system can also include more than one reflector, thereby establishing a multi-reflector system. The multiple reflectors can be located in the same beam path. Alternatively, the reflectors can be assigned to different feed antennas such that they are located in different beam paths established between the respective antennas and the test position.

[0025] The orthogonal mode transducer assembly can be oriented relative to at least one reflector such that at least two feed antennas connected to the orthogonal mode transducer assembly point to the at least one reflector. Due to the minimized antenna phase center spacing and the fact that the output interfaces are located on the same planar side surface of the orthogonal mode transducer assembly, the corresponding feed antennas can point to the (same) reflector simultaneously. Thus, a feed switcher is not required, as different feed antennas can transmit / receive electromagnetic signals reflected correspondingly via the (same) reflector.

[0026] On the other hand, there is provided an air measurement system including at least two reflectors, wherein the first reflector of the at least two reflectors is a main reflector configured as a parabolic reflector, and wherein the second reflector of the at least two reflectors is a sub-reflector configured as a non-parabolic reflector. Thus, a multi-reflector system is provided, where each reflector is used to establish an indirect far-field (IFF) condition, which is used to test the device under test under real conditions (i.e., far-field conditions).

[0027] On the other hand, an air measurement system is provided that includes an RF shielded chamber housing an orthogonal mode transducer assembly. The RF shielded chamber can appropriately shield interfering and disturbing signals, thereby improving the test accordingly.

[0028] Additionally, the air measurement system can include measurement equipment connected to the orthogonal mode transducer assembly. The measurement equipment can provide respective different polarization signals that are forwarded to the orthogonal mode transducer assembly (specifically its input interface). Thus, the measurement equipment can include a signal generator, where the measurement equipment is connected to respective waveguides that are connected to the input interface such that the generated signals are forwarded to the orthogonal mode transducer assembly, i.e., signals of different polarizations.

[0029] Furthermore, an analysis device can be provided that is connected to the orthogonal mode transducer assembly and / or the device under test to receive the signals to be analyzed to characterize the behavior of the device under test during the test.

[0030] Moreover, the air measurement system can include a locator system for the device under test. The locator system can be used to rotate the device under test during the test to fully characterize the device under test, especially in multiple directions. In fact, the locator system can be a three-dimensional (3D) locator system, such as a mobile phone locator and a tablet computer locator in the case of testing a mobile phone or more precisely a tablet computer.

[0031] Generally, the locator system ensures highly accurate azimuth and elevation positioning of the device under test, especially in one or more quiet zones.

[0032] In fact, the total radiated power (TRP) measurement can be performed accurately and quickly.

[0033] According to an embodiment, the orthogonal mode transducer assembly includes three orthogonal mode transducers. Thus, three output interfaces are provided, which are respectively connected to the orthogonal mode transducers. Additionally, respective feeding antennas are connected to the orthogonal mode transducers via the corresponding output interfaces. Therefore, three different frequency bands can be tested through the orthogonal mode transducer assembly, thereby ensuring broadband testing of the device under test.

[0034] Specifically, the first of the three orthogonal mode transducers is assigned to the frequency range of 24 - 42 GHz. The second of the three orthogonal mode transducers is assigned to the frequency range of 35 - 60 GHz. The third of the three orthogonal mode transducers is assigned to the frequency range of 60 - 90 GHz. Each orthogonal mode transducer is connected to a dedicated feeding antenna via the output interface, and the dedicated feeding antenna can operate within the corresponding frequency range mentioned above. Therefore, three different frequency bands can be tested simultaneously through the orthogonal mode transducer assembly without repositioning the device under test or more precisely the feeding antenna, thereby significantly improving the overall setup.

[0035] As shown above, the different frequency bands associated with three different orthogonal mode transducers at least partially overlap, thus ensuring the broadband test characteristics of the orthogonal mode transducer assembly. In fact, the orthogonal mode transducer assembly covers a frequency range from 24 GHz to 90 GHz.

[0036] Generally, a compact multi-band orthogonal mode transducer assembly is provided, which has two or more orthogonal mode transducers, such as three orthogonal mode transducers. The input interface associated with one orthogonal mode transducer provides different polarization signals, such as orthogonal polarization signals, such as horizontal polarization signals and vertical polarization signals. Each orthogonal mode transducer of the multi-band orthogonal mode transducer assembly can divide the corresponding signal received via the output interface into two components that are orthogonally polarized with respect to each other, and the components are forwarded to the input interface. In addition, each orthogonal mode transducer is also configured to combine the orthogonally polarized signals received via the input interface into a combined signal that is forwarded to the output interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated, as they become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, in which:

[0038] - Figure 1 A general overview of an air measurement system according to an embodiment of the present invention is schematically shown.

[0039] - Figure 2 Shows Figure 1 An isometric view of the orthogonal mode transducer assembly used in the air measurement system of

[0040] - Figure 3 Shows Figure 2 A cross-sectional view of the orthogonal mode transducer assembly of

[0041] - Figure 4 A general overview of a plurality of different orthogonal mode transducer components is shown, where each of the different orthogonal mode transducer components is shown from the opposite side. DETAILED DESCRIPTION

[0042] The following detailed description, presented in conjunction with the accompanying drawings, in which like reference numerals refer to like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided only as an example or illustration and should not be construed as preferred or superior to other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the exact forms disclosed.

[0043] For the present disclosure, the phrase "at least one of A, B, and C" refers, for example, to (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when listing more than three elements. In other words, the term "at least one of A and B" generally refers to "A and / or B", i.e., A alone, B alone, or A and B.

[0044] Figure 1 An air measurement system 10 is shown that is used to test a device under test 12.

[0045] The air measurement system 10 includes an anechoic chamber or more precisely an RF shielding chamber 14 that houses the device under test 12 and an orthogonal mode transducer (OMT) assembly 16 that is used to test the device under test 12, as will be described in more detail below.

[0046] The air measurement system 10 further includes a locator system 18 for the device under test 12, where the locator system 18 can be configured to rotate the device under test 12 at least along one rotation axis during testing, particularly in a three-dimensional manner, i.e., along at least two rotation axes. The device under test 12 is mounted on the locator system 18.

[0047] In addition, the air measurement system 10 includes a measurement device 20 and an analysis device 22 that are suitably connected to the orthogonal mode transducer assembly 16 and / or the locator system 18. Furthermore, the signals received by the device under test 12 can be forwarded to the analysis device 22 such that a corresponding communication connection is also established between the device under test 12 and the analysis device 22. In addition, the measurement device 20 can be connected to the device under test 12.

[0048] The corresponding connection between the measurement device 20 and the orthogonal mode transducer assembly 16 can be established by a waveguide that forwards different polarization signals to the orthogonal mode transducer assembly 16.

[0049] In addition, in Figure 1 it is shown that the air measurement system 10 includes two reflectors 24, namely a main reflector 26 and a sub-reflector 28. Depending on the test scenario, the orthogonal mode transducer assembly 16 can be oriented towards the main reflector 26 or the sub-reflector 28.

[0050] In the illustrated embodiment, the main reflector 26 is formed as a parabolic reflector, while the sub-reflector 28 is formed as a non-parabolic reflector.

[0051] One or more reflectors 24 can be oriented towards the device under test 12 (particularly the test position where the device under test 12 is positioned for testing purposes). Thus, a beam path is established between the orthogonal mode transducer assembly 16 and the device under test 12 via one or more corresponding reflectors 24.

[0052] In the illustrated embodiment, the orthogonal mode transducer assembly 16 is connected to the feed antenna 30, which has different dimensions and / or shapes for use in different frequency bands, as will be discussed in more detail later.

[0053] In addition, Figure 1 it is shown that the feed antenna 30 is connected to the common side surface 32 of the orthogonal mode transducer assembly 16, which is shown in more detail in Figure 2 as will be described later. Thus, the feed antenna 30 is directed towards one or more corresponding reflectors 24.

[0054] Generally, this ensures that broadband over-the-air (OTA) measurements within the anechoic chamber or more precisely the RF shielded chamber 14 can be performed without a feed switch or more precisely an antenna positioner.

[0055] Since the feed antenna 30 is connected at the same common side surface 32, it is ensured that the feed antenna 30 is substantially located at the focus of one or more corresponding reflectors 24. This means that due to the corresponding shape of the orthogonal mode transducer assembly 16, the deviation from the focus is minimized, which will be discussed in more detail below with reference to Figures 2 to 4 as the corresponding design of the orthogonal mode transducer assembly 16 becomes clear from Figures 2 to 4 this.

[0056] In Figure 2 this, the orthogonal mode transducer assembly 16 is shown in an isometric view. It is clear that the orthogonal mode transducer assembly 16 has several individually formed orthogonal mode transducer parts 34, which are stacked linearly on top of each other, thus providing a sandwich of orthogonal mode transducer parts 34.

[0057] In the illustrated embodiment, four orthogonal mode transducer parts 34 are shown, which together form three different orthogonal modes transducers 36, as shown in Figure 3 this, which shows a cross-sectional view of the orthogonal mode transducer assembly 16.

[0058] Additionally, Figure 3 it is shown that each of the orthogonal mode transducers 36 is connected to an output interface 38 located at the common side surface 32 of the orthogonal mode transducer assembly 16, where the common side surface 32 is planar.

[0059] Thus, the output interface 38 and / or the feed antenna 30 connected thereto are located in a common plane.

[0060] Furthermore, each orthogonal mode transducer 36 is assigned two input interfaces 40, via which signals of different polarizations are forwarded to the dedicated orthogonal mode transducer 36.

[0061] Accordingly, the illustrated orthogonal mode transducer assembly 16 has a total of six input interfaces 40 because three different orthogonal mode transducers 36 are provided.

[0062] In Figure 3 and Figure 4 it is further shown that the respective input interfaces 40 are each incorporated into a corresponding waveguide transition 42. Each waveguide transition 42 terminates at a corresponding orthogonal mode transducer 36.

[0063] However, the waveguide transition 42 can be a straight waveguide transition or an angled waveguide transition, depending on the corresponding orthogonal mode transducer 36, in particular its relative position in the stack of orthogonal mode transducer components 34. This will be described in more detail later.

[0064] Figure 4 It is further shown that each orthogonal mode transducer 36 is formed by a structured portion 44 provided at each contact side 46, via which the adjacent orthogonal mode transducer components 34 are in contact with each other in the Figure 2 and Figure 3 illustrated assembled state.

[0065] In other words, the orthogonal mode transducer components 34 located in the center or more precisely sandwiched between the outer orthogonal mode transducer components 34 each have two contact sides 46. Thus, the central or more precisely sandwiched orthogonal mode transducer group components 34 together with their adjacent orthogonal mode transducer components 46 partially form two different orthogonal mode transducers 36.

[0066] The orthogonal mode transducer assembly 16 according to the illustrated embodiment has four orthogonal mode transducer components 34, such that there is provided an upper orthogonal mode transducer component 34 shown on the Figure 4 left side and a lower orthogonal mode transducer component 34 shown on the Figure 4 right side. Each orthogonal mode transducer component 34 is shown from two opposite sides.

[0067] In addition, two central or intermediate orthogonal mode transducer components 34 are provided, which are in direct contact with two different orthogonal mode transducer components 34 on opposite sides in the assembled state.

[0068] Figure 4 It is shown that the central or more precisely intermediate orthogonal mode transducer components 34 have structured portions 44 on both opposite sides because these orthogonal mode transducer components 34 interact with their adjacent orthogonal mode transducer components 34.

[0069] In fact, the two central or intermediate orthogonal mode transducer components 34 together form a first orthogonal mode transducer 36, as Figure 3As shown, it is labeled as OMT1. The first orthogonal mode transducer 36 ("OMT1") is assigned to the frequency range from 24 GHz to 42 GHz.

[0070] As Figure 3 and Figure 4 shown, the first orthogonal mode transducer 36 ("OMT1") is connected to two straight waveguide transitions 42 that are oriented perpendicular to each other. One of the two straight waveguide transitions 42 extends from the side opposite the common side surface 32 where the output interface 38 is provided, towards the first orthogonal mode transducer 36 ("OMT1"). The other of the two straight waveguide transitions 42 is arranged perpendicular to it.

[0071] In addition, both the intermediate or central orthogonal mode transducer components 34 interact with the upper orthogonal mode transducer component 34 or the lower orthogonal mode transducer component 34 respectively, in order to establish the second orthogonal mode transducer 36 ("OMT2") associated with the frequency range from 35 GHz to 60 GHz and the third orthogonal mode transducer 36 ("OMT3") assigned to the frequency range from 60 GHz to 90 GHz.

[0072] As Figure 3 and Figure 4 shown, both the second orthogonal mode transducer 36 ("OMT2") and the third orthogonal mode transducer 36 ("OMT3") are respectively connected to straight waveguide transitions 42 and angled waveguide transitions 42, where each angled waveguide transition 42 has a portion 48 with a ninety-degree (90°) angle.

[0073] The angled waveguide transitions 42 each terminate at a common side 50, which is perpendicular to the common side surface 32 where the output interface 38 is provided.

[0074] In addition to the orthogonal mode transducers 36 being established by two adjacent orthogonal mode transducer components 34 that are in contact with each other via their contact sides 44, the corresponding input interfaces 40 can also be established together by two adjacent orthogonal mode transducer components 34, for example, those incorporated into the angled waveguide transitions 42. However, one straight waveguide transition 42 that terminates at the first orthogonal mode transducer 36 ("OMT1") is also established by two adjacent orthogonal mode transducer components 34, namely the one that extends from the side opposite the common side surface 32 of the orthogonal mode transducer assembly 16.

[0075] Generally, the orthogonal mode transducer assembly 16 includes 2×N - (N - 1) individually formed orthogonal mode transducer components 34, where N corresponds to the number of orthogonal mode transducers 36.

[0076] In the illustrated embodiment, the orthogonal mode transducer assembly 16 has four separately formed orthogonal mode transducer parts 34, and three of the orthogonal mode transducers 36 are established by these orthogonal mode transducer parts 34. Thus, N equals 3 (N = 3), such that 2×3-(3-1)=4 separately formed orthogonal mode transducer parts 34 are arranged as shown.

[0077] Figure 2 An end cap 52 is also shown as being connected to the common side surface 32 of the orthogonal mode transducer assembly 16, where the end cap 52 provides an adapter for a respective feed antenna 30 ( Figure 2 not shown in the figure) to connect to the output interface 38. The end cap 52 has a plate-like base 54 and a waveguide 56, where the end cap 52 is fixedly connected to the common outer surface 32 via the plate-like base 54. The waveguide 56 is used to connect the respective feed antenna 30 accordingly.

[0078] Due to the design of the orthogonal mode transducer assembly 16, the antenna phase center spacing between the feed antennas 30 to be connected to the orthogonal mode transducer assembly 16 is ensured to be less than 2 cm, especially less than 1.8 cm. Thus, during the corresponding broadband tests, there is no need to move the feed antennas 30 and / or the device under test 12, thereby significantly reducing the total cost.

[0079] In the assembled state, the separately formed orthogonal mode transducer parts 34 are mechanically connected to each other by fastening elements (e.g., by screws). In addition, the end cap 52 can also be connected by a fastening element such as a screw.

[0080] Certain embodiments disclosed herein, particularly corresponding one or more modules and one or more units, utilize circuitry (e.g., one or more circuits) to implement the standards, protocols, methods, or techniques disclosed herein, operably couple two or more components, generate information, process information, analyze information, generate signals, encode / decode signals, convert signals, transmit and / or receive signals, control other devices, etc. Any type of circuitry can be used.

[0081] In an embodiment, the circuitry includes, among other things, one or more computing devices such as a processor (e.g., a microprocessor), a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a system on a chip (SoC), etc. or any combination thereof, and can include discrete digital or analog circuit elements or electronic devices or a combination thereof. In an embodiment, the circuitry includes hardware circuit implementations (e.g., implementations in analog circuitry, implementations in digital circuitry, etc., and combinations thereof).

[0082] In an embodiment, a circuit system includes a combination of circuitry and a computer program product having software or firmware instructions stored on one or more computer-readable memories that work together to cause the device to perform one or more of the protocols, methods, or techniques described herein. In an embodiment, a circuit system includes circuitry that requires software, firmware, etc. for operation, such as, for example, a microprocessor or a portion of a microprocessor. In an embodiment, a circuit system includes one or more processors or portions thereof along with accompanying software, firmware, hardware, etc.

[0083] This application may refer to quantities and numbers. Unless otherwise specified, these quantities and numbers should not be considered limiting, but rather examples of possible quantities or numbers associated with this application. Also in this regard, this application may use the term "plurality" to refer to a quantity or number. In this regard, the term "plurality" refers to any number greater than one, such as two, three, four, five, etc. The terms "about", "substantially", "approximately", etc. mean plus or minus 5% of a specified value.

Claims

1. An air measurement system for testing a device under test (12), wherein, the air measurement system (10) includes an orthogonal mode transducer (OMT) assembly (16), the orthogonal mode transducer assembly (16) having a plurality of individually formed orthogonal mode transducer parts (34) forming at least two orthogonal mode transducers (36), wherein, the orthogonal mode transducer assembly (16) has at least two output interfaces (38) for a feed antenna (30), wherein, each of the at least two output interfaces (38) is connected to a dedicated orthogonal mode transducer (36), wherein, two input interfaces (40) are associated with each of the orthogonal mode transducers (36), wherein, each of the input interfaces (40) is incorporated into a corresponding waveguide transition (42), the waveguide transition terminating at the corresponding orthogonal mode transducer (36) associated with the corresponding input interface (40), the air measurement system is characterized in that the plurality of orthogonal mode transducer parts (34) are linearly stacked together and the at least two output interfaces (38) are located on a planar common side surface (32) of the orthogonal mode transducer assembly (16), wherein, adjacent orthogonal mode transducer parts (34) face each other via corresponding contact sides (46), and wherein, the corresponding contact sides (46) of the adjacent orthogonal mode transducer parts (34) have structured portions (44), the structured portions (44) together forming one of the at least two orthogonal mode transducers (36).

2. The air measurement system according to claim 1, wherein, the plurality of orthogonal mode transducer parts (34) are oriented relative to each other such that two straight waveguide transitions (42) are provided, both of the two straight waveguide transitions (42) terminating at the same orthogonal mode transducer (36).

3. The air measurement system according to claim 1 or 2, wherein, the plurality of orthogonal mode transducer parts (34) are oriented relative to each other such that one straight waveguide transition and one angled waveguide transition are provided, both of them terminating at the same orthogonal mode transducer (36).

4. The air measurement system according to claim 1, wherein, the orthogonal mode transducer assembly (16) includes 2×N-(N - 1) individually formed orthogonal mode transducer parts (34), where N corresponds to the number of orthogonal mode transducers (36).

5. The air measurement system according to claim 1, wherein, at least two feed antennas (30) are provided, the at least two feed antennas (30) being respectively connected to the at least two output interfaces (38) of the orthogonal mode transducer assembly (16).

6. The air measurement system according to claim 1, wherein, at least two waveguides (56) are provided, the at least two waveguides (56) being respectively connected to the at least two input interfaces (40) of the orthogonal mode transducer assembly (16).

7. The air measurement system according to claim 1, wherein the air measurement system (10) includes at least one reflector (24).

8. The airborne measurement system according to claim 7, wherein at least two feed antennas (30) are provided, which are respectively connected to at least two output interfaces (38) of the orthogonal mode transducer assembly (16), and wherein one of the at least two feed antennas (30) is substantially located at the focus of the at least one reflector (24).

9. The airborne measurement system according to claim 1, wherein, the airborne measurement system (10) includes at least two reflectors (24), wherein the first reflector (24) of the at least two reflectors (24) is the main reflector (26) configured as a parabolic reflector, and wherein the second reflector (24) of the at least two reflectors (24) is the sub-reflector (28) configured as a non-parabolic reflector.

10. The airborne measurement system according to claim 1, wherein, the airborne measurement system (10) includes an RF shielding chamber (14) that houses the orthogonal mode transducer assembly (16).

11. The airborne measurement system according to claim 1, wherein, the airborne measurement system (10) includes a measurement device (20) connected to the orthogonal mode transducer assembly (16).

12. The airborne measurement system according to claim 1, wherein, the airborne measurement system (10) includes a locator system (18) for the device under test (12).

13. The airborne measurement system according to claim 1, wherein, the orthogonal mode transducer assembly (16) includes three orthogonal mode transducers (36).

14. The airborne measurement system according to claim 1, wherein the at least two output interfaces (38) are arranged relative to each other such that the antenna phase center spacing is less than 2 centimeters.

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