Millimeter-wave vector network analyzer

Abstract

Disclosed and described herein are embodiments of millimeter-wave (mmW) vector network analyzers (VNAs). In one embodiment, the mmW VNA includes a conventional automotive / industrial mmW radar circuit board that has been modified (i.e., connectorized) to connect to one or more devices. The mmW radar circuit board includes a multiport board and an mmW radar chip having multiple receive (Rx) channels and multiple transmit (Tx) channels, connectors provided in place of an onboard antenna to connect the Rx and Tx channels to one or more devices, and one or more off-axis parabolic mirrors used to transmit signals to, from, and / or through a sample using the devices.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 454,188, filed on May 23, 2023, which is hereby incorporated by reference in its entirety and made a part of this specification.

Background Art

[0002] Millimeter - wave (mmW) radar chips operating in the 24 GHz, 60 GHz, and 80 GHz ISM bands are commercially available from multiple vendors for automotive and industrial sensing applications. Future radars may also operate in the 140 GHz band and 225 GHz band, and may further increase beyond 225 GHz. Typically, these radars are used with those in which the transmit antenna and the receive antenna are directly formed on a printed circuit board (PCB) (see, for example, FIG. 1). FIG. 1 shows a comparison between a conventional PCB for mmW radar and a PCB according to an embodiment of the present invention. The conventional usage form is based on multiple - input multiple - output (MIMO) radar technology. At the core of mmW radar chip technology, there are integrated mmW transmit circuits and receive circuits, and further circuit hardware for digital signal processing is included (see, for example, automotive radar products of Texas Instruments).

[0003] However, these chips are specifically designed to be used as conventional radars that can provide real - time sensing, and thus their use as a vector network analyzer (VNA) has not been conventionally considered. A VNA is a major test instrument for RF and mmW circuit and component design. Nevertheless, at higher frequencies, the cost of a VNA increases exponentially. In particular, VNA equipment in the mmW band is extremely expensive.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, a VNA that overcomes some of the challenges in the relevant technological field, as described above, is desired. [Means for solving the problem]

[0005] Described and disclosed herein are VNAs utilizing conventional frequency-modulated continuous-wave (FMCW) radar chips with multiple inputs and multiple outputs (MIMO), developed for automotive and industrial sensing applications.

[0006] Disclosed and described herein are VNAs, including connectorized versions of conventional radar printed circuit boards. The disclosed mmW VNA embodiments have been demonstrated to perform as highly sensitive, measurement-grade instruments, and their use in the electrical characterization of materials in the mmW band has also been shown. This includes imaging in reflection and transmission modes, as well as dielectric, permeability, and loss characteristics. This innovative demonstration of using a radar chip as a VNA provides an extremely low-cost alternative for mmW measurements of scattering parameters of RF devices and circuits.

[0007] In one embodiment, a millimeter-wave (mmW) vector network analyzer (VNA) is disclosed. One embodiment of the mmW VNA includes a mmW radar circuit board modified to connect to one or more devices, the mmW radar circuit board includes a plurality of board ports including a plurality of receive (Rx) channels and a plurality of transmit (Tx) channels, a mmW radar chip, and a plurality of connectors. One or more of the plurality of Rx channels and one or more of the plurality of Tx channels are connected to one or more devices using the plurality of connectors. The mmW VNA further includes one or more off-axis parabolic mirrors, the one or more off-axis parabolic mirrors used to transmit signals to, from, and / or through a sample using a device.

[0008] In some cases, multiple board ports may include seven board ports, each containing four Rx channels and three Tx channels.

[0009] In some cases, multiple connectors replace the onboard antenna on the mmW radar circuit board.

[0010] In some cases, leads are used to connect the Rx and Tx channels to one or more devices. One or more devices may include one or more Tx antennas and / or one or more Rx antennas and / or one or more Tx / Rx combination antennas. In some examples, one or more devices may further include one or more circulators. In some examples, one or more devices may further include one or more external directional couplers. In some examples, one or more devices may further include one or more integrated directional couplers.

[0011] In some examples of mmW VNAs, measurement scenarios using a mmW VNA are considered with a target rotated in the azimuthal and / or elevation directions to perform transmitted and reflected imaging as a function of the angle of incidence.

[0012] In some examples of mmW VNAs, it is used to characterize samples, including multi-port, calibrated S-parameter measurements, antenna characterization (including input impedance and antenna pattern), scattering cross-section measurements, material characterization (dielectric constant and permeability), and imaging.

[0013] Other devices, systems, methods, features, and / or advantages will be apparent, or may be apparent, to a person skilled in the art by examining the following drawings and detailed description. All such additional systems, methods, features, and / or advantages are intended to be contained in this specification and protected by the appended claims.

[0014] The following detailed description will be better understood when read in conjunction with the accompanying drawings. The accompanying drawings show one or more of the various embodiments of this disclosure. However, please understand that the various embodiments of this disclosure are not limited to the exact arrangements and equipment shown in the drawings. [Brief explanation of the drawing]

[0015] [Figure 1] This is a comparison of the PCB of a conventional mmW radar with the PCB of an embodiment of the present invention. [Figure 2] This is an explanatory diagram of one embodiment of a millimeter-wave vector network analyzer (VNA) that can be used in a transmission measurement scenario. [Figure 3] This is an explanatory diagram of one embodiment of a mmW VNA that can be used in transmit and reflectance measurement scenarios. [Figure 4] Figures A and B illustrate one embodiment of a mmW VNA that can be used in a complete two-port transmit and reflectance measurement scenario. [Figure 5] This is an explanatory diagram of one embodiment of a mmW VNA that can be used in a single-port (refractometer) scenario. [Figure 6] This is an explanatory diagram of one embodiment of a mmW VNA that can be used in a single-port (refractometer) imaging measurement scenario. [Figure 7] This is an explanatory diagram of one embodiment of a mmW VNA that can be used in transmission and reflection imaging scenarios. [Figure 8] This is an explanatory diagram of one embodiment of a mmW VNA that can be used in angle-dependent transmission and reflection imaging measurement scenarios. [Figure 9] This is an explanatory diagram of one embodiment of a mmW VNA that can be used as a single port (refractometer) using an external directional coupler. [Figure 10]FIG. 0 is an explanatory view of one embodiment of a mmW VNA that can be used as a single port (reflectometer) using an integrated directional coupler. [Figure 11] A and B show typical signals measured by the mmW VNA when highly reflective terminations called reflection standards are applied to both ports. A shows raw measurement data and B shows calibrated measurement data. [Figure 12] A and B show typical signals called through standards measured by the mmW VNA when both ports are connected together. A shows raw measurement data and B shows calibrated measurement data. [Figure 13] A and B show typical signals measured by the mmW VNA when a material sample (3.085 mm thick thermoplastic elastomer - TPO) is placed between the two VNA ports. A shows raw measurement data and B shows calibrated measurement data. [Figure 14] A and B show typical signals measured by the mmW VNA when a material sample (1.875 mm thick acrylic) is placed between the two VNA ports. A shows raw measurement data and B shows calibrated measurement data. [Figure 15] A and B show the extracted material properties (i.e., dielectric constant) of two representative material samples. DETAILED DESCRIPTION OF THE INVENTION

[0016] Before the methods and systems are disclosed and described, it should be understood that the methods and systems are not limited to a particular synthesis method, a particular component, or a particular composition. Also, it should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0017] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" a particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about", it will be understood that the particular value forms another embodiment. It should further be understood that each endpoint of a range is significant both in relation to the other endpoint and independently of the other endpoint.

[0018] "Optional" or "optionally" means that the subsequent described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0019] Throughout the description and claims of this specification, the words "comprise", "comprising", and "comprises" and variations thereof mean "including, but not limited to", and are not intended to (and do not) exclude other additives, components, elements or steps. "Exemplary" means "an example of" and is not intended to convey an indication of a preferred or ideal embodiment. "Such as" is used for illustrative purposes and not for limiting purposes.

[0020] Components that may be used to carry out the disclosed methods and systems are disclosed herein. Where these and other components are disclosed herein, and where combinations, subsets, interactions, groups, etc., of these components are disclosed, specific designations for each of these various individual and collective combinations and permutations may not be expressly disclosed, but each is understood to be specifically contemplated and described herein for all methods and systems. This applies to all aspects of this application, including, but not limited to, steps in the disclosed methods. Therefore, where there are various additional steps that can be carried out, each of these additional steps is understood to be carry out in any particular embodiment or combination of embodiments of the disclosed methods.

[0021] The methods and systems of the present invention can be more readily understood by referring to the following detailed description of preferred embodiments and the examples contained herein, as well as the drawings and their preceding and succeeding descriptions.

[0022] Figure 2 is an illustrative diagram of one embodiment of a millimeter-wave vector network analyzer (VNA). This embodiment includes a conventional automotive / industrial mmW radar circuit board 102 that has been modified (i.e., connectorized) to connect to external leads 104 and device 106. The mmW radar circuit board 102 shown in Figure 1 is a 7-port board with four receive (Rx) channels 108 and three transmit (Tx) channels, including an mmW radar chip 118. The number and configuration of other ports, Tx channels, and Rx channels are contemplated within the scope of this disclosure. Rather than having an onboard antenna, the mmW radar circuit board 102 here has connectors 108, 110 instead of an onboard antenna. As shown in Figure 1, leads 104-a and 104-b are used to connect ports 108, 110 to devices 106-a (Rx antenna) and 106-b (transmit antenna) using connectors 108, 110. The embodiment in Figure 1 further includes off-axis parabolic mirrors 112 and 114 used to parallelize the transmitted signal to, from, and / or through sample 116, which receive the subsequent signal using transmitting antenna 106-b and receiving antenna 106-a connected to their respective ports on the PCB. The received signal can be used to determine the characteristics of sample 116, which include multi-port calibrated S-parameter measurements, antenna characterization (including input impedance and antenna pattern), scattering cross-section measurements, material characterization (relative permittivity and permeability), imaging, etc., providing the full utility of a conventional VNA.

[0023] Figure 3 is an explanatory diagram of one embodiment of a mmW VNA that can be used in a transmission and reflection measurement scenario. In this scenario, reflections from sample 116 can be acquired and measured. This is achieved by a second Rx antenna 106-c (Rx2) and a circulator 120, where the reflected signal is collected by the second Rx antenna 106-c (Rx2) and led to the Rx port of the mmW radar circuit board 102 using the circulator 120, a second Rx lead 104-c, and an Rx connector 108.

[0024] Figures 4A and 4B illustrate one embodiment of a mmW VNA that can be used in a complete two-port transmit and reflectance measurement scenario. Figure 4A shows an embodiment of a mmW VNA including two circulators, additional leads connected to connectors 108 and 110, and a forward-facing Tx antenna that can be used to perform measurements including reflections in the forward direction. Figure 4B shows an embodiment of a mmW VNA including two circulators, additional leads connected to connectors 108 and 110, and a rear-facing Tx antenna that can be used to perform measurements including reflections in the rear direction.

[0025] Figure 5 is an illustrative diagram of one embodiment of a mmW VNA that can be used in a single-port (refractometer) scenario. In this scenario, a single Rx / Tx antenna is connected to the Rx and Tx ports of the mmW radar circuit board 102 using a circulator. This scenario acquires reflections from sample 116.

[0026] Figure 6 is an illustrative diagram of one embodiment of a mmW VNA that can be used in a single-port (refractometer) imaging measurement scenario. This scenario acquires reflections from a sample 116 located in the xy plane. This can be used for automated movement of the sample 116 in the xy plane for raster scan reflection imaging.

[0027] Figure 7 is an explanatory diagram of one embodiment of a mmW VNA that can be used in a transmit and reflect imaging scenario. This scenario acquires not only transmission through sample 116 but also reflection from sample 116 located in the xy plane. This can be used for automated movement of sample 116 in the xy plane for raster scan transmit and reflect imaging.

[0028] Figure 8 is an illustrative diagram of one embodiment of a mmW VNA that can be used in angle-dependent transmit and reflect imaging measurement scenarios. Here, sample 116 is rotated in the azimuth and / or elevation directions for transmit and reflect imaging as a function of the incidence angle.

[0029] Figure 9 is an explanatory diagram of one embodiment of a mmW VNA that can be used as a single port (refractometer) using an external directional coupler.

[0030] Similarly, Figure 10 is an explanatory diagram of one embodiment of a mmW VNA that can be used as a single-port (refractometer) using an integrated directional coupler. Here, the directional coupler is integrated into the mmW radar circuit board 102. A similar configuration provides a complete two-port VNA using two integrated directional couplers. Figures 11A and 11B show typical signals measured by the mmW VNA when a highly reflective termination called a reflection standard is applied to both ports. Figure 11A shows the raw measurement data, and Figure 11B shows the measured data after calibration.

[0031] Figures 12A and 12B show typical signals called through standards, measured by the mmW VNA when both ports are connected together. Figure 12A shows the raw measurement data, and Figure 12B shows the measurement data after calibration.

[0032] Figures 13A and 13B show typical signals measured by a mmW VNA when a material sample (3.085 mm thick thermoplastic elastomer - TPO) is placed between two VNA ports. Figure 13A shows the raw measurement data, and Figure 13B shows the calibration measurement data.

[0033] Figures 14A and 14B show typical signals measured by a mmW VNA when a material sample (1.875 mm thick acrylic) is placed between two VNA ports. Figure 14A shows the raw measurement data, and Figure 14B shows the measurement data after calibration.

[0034] Figures 15A and 15B show the extracted material properties (i.e., dielectric constant) of two representative material samples.

[0035] conclusion

[0036] While methods and systems have been described in relation to preferred embodiments and specific examples, the embodiments described herein are intended to be illustrative and not restrictive in any way, and are not intended to limit the scope to any specific embodiment described.

[0037] Unless otherwise expressly provided, none of the methods described herein are intended to be construed as requiring their steps to be performed in a specific order. Therefore, where a claim for a method does not actually describe the order in which its steps should be followed, or where it is not otherwise specifically stated in the claim or description that the steps should be limited to a particular order, no order should ever be inferred. This also applies to any possible ambiguity for interpretation, including logical issues relating to the arrangement of steps or operational flows, plain meanings arising from grammatical construction or punctuation, and the number or type of embodiments described in the specification.

[0038] Throughout this application, various publications are referenced. The disclosures of these publications, in their entirety, are incorporated herein by reference to more fully describe the state of the art in which the Method and System belong.

[0039] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit. Other embodiments will also be apparent to those skilled in the art from the considerations herein and the practices disclosed herein. This specification and the examples are intended to be considered illustrative only, and the true scope and spirit are indicated by the following claims.

Claims

1. A millimeter-wave (mmW) vector network analyzer (VNA), mmW radar circuit board improved to connect to one or more devices, wherein the mmW radar circuit board is Multiple board ports including multiple receiving (Rx) channels and multiple (Tx) channels, mmW radar chip and, Includes multiple connectors, The mmW radar circuit board, wherein one or more of the plurality of Rx channels and one or more of the plurality of Tx channels are connected to one or more of the plurality of devices using the plurality of connectors, The device includes one or more off-axis parabolic mirrors, the one or more off-axis parabolic mirrors being used to transmit signals to, from, and / or through a sample. mmW VNA.

2. The mmW VNA according to claim 1, wherein the plurality of substrate ports include seven substrate ports, each containing four Rx channels and three Tx channels.

3. The mmW VNA according to claim 1 or claim 2, wherein the plurality of connectors replace the onboard antenna on the mmW radar circuit board.

4. The mmW VNA according to any one of claims 1 to 3, wherein lead wires are used to connect the Rx and Tx channels to one or more devices.

5. The mmW VNA according to any one of claims 1 to 4, wherein the one or more devices include one or more Tx antennas and / or one or more Rx antennas and / or one or more Tx / Rx combination antennas.

6. The mmW VNA according to claim 5, wherein the one or more devices further include one or more circulators.

7. The mmW VNA according to any one of claims 5 or 6, wherein the one or more devices further comprises one or more externally oriented couplers.

8. The mmW VNA according to any one of claims 5 or 6, wherein the one or more devices further comprises one or more integrated directional couplers.

9. A measurement scenario using the mmW VNA is considered, in which the target is rotated in the azimuthal and / or elevation direction for transmission and reflection imaging as a function of the angle of incidence, according to any one of claims 1 to 8.

10. The mmW VNA according to any one of claims 1 to 9, wherein the mmW VNA is used to determine the characteristics of the sample, including multi-port calibrated S-parameter measurement, antenna characteristic evaluation (including input impedance and antenna pattern), scattering cross-section measurement, material characterization (relative permittivity and permeability), and imaging.

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