Patent Grant
12148997
The present disclosure relates generally to an open waveguide antenna, and more particularly to an open waveguide antenna system.
Previous generations of mmWave systems have been constructed utilizing several special purpose MMIC (Monolithic Microwave Integrated Circuit) devices, which typically includes, a transmitter integrated circuit, a receiver integrated circuit, and a local oscillator circuit to synchronize these systems together. An example of this construction is a Continental ARS-4A long range radar sensor, an example of which can be found at http://img009.hc360.cn/k2/M0A/BF/43/wKhQxVq53tuEEmCQAAAAACS5hks768.pdf. By virtue of the distributed nature of the transmitter and receiver MMIC in these systems, the distance between radiators and MMICs could be reduced, resulting in a tolerable insertion loss despite the electrically large antenna aperture produced by the radar. Recently, CMOS MMIC devices have become available, which combine TX and RX functionality into a single chip. From a cost perspective, these systems are advantageous, reducing not only die cost, but assembly and manufacturing costs for the radar manufacturer. This has the effect of centralizing the MMIC, and increasing the transmission line distances between antenna and MMIC. Additionally, this centralization reduces the complexity of RF signal routing between devices.
The two trends of lengthening transmission lines and reducing complexity of routed signals have made alternative methods of connecting the antenna to the MMIC more attractive. A common RF interconnection method is to use an etched trace on a printed circuit board. This transmission line structure is typically a microstrip (signal layer separated from ground by a dielectric) or co-planar waveguide (microstrip with grounding structures next to the trace on the signal layer). This type of transmission line will exhibit an insertion loss of around 1 dB per inch at 79 GHz when produced on a “best in class” PCB material, and 2 dB per inch when produced on a typical PCB material.
As MMICs have become increasingly integrated, and the number of routed RF transmission lines on the PCB has decreased, an old transmission structure becomes more applicable. Waveguides had been explored theoretically in the 1890s, and practically adopted since the 1940s. At 79 GHz a rectangular waveguide will exhibit an insertion loss of around 0.25 dB per inch. Applied to a 3 inch long transmission line, in practice a 79 Ghz system would lose 50% of its power in a microstrip line built on a best in class laminate, 75% of its power on a typical PCB, but only about 16% of its power in waveguide. In a radar system, this difference in loss is seen both from the MMIC Transmitter block to the antenna, and from the antenna to the MMIC receiver block. Thus, the “two way” loss is double that of the above loss figures. This makes the reduction in loss even more attractive to the designers of radar systems.
For designers employing waveguide feed networks in mmWave radar or communications systems, there are three additional considerations that dictate system architecture and performance. The first is how to transfer the power from the MMIC to the waveguide (the transition), the second is how to transfer power from the waveguide into free space (the antenna), and finally for most systems, cost is a critical consideration in addition to the system performance.
Two primary methods have been described for the transfer of power between the MMIC and waveguide.
The first transition approach is the utilization of a transition from the package to a printed circuit board. This transition often involves several sub transitions. First power is transferred from the semiconductor die to a fan-out or re-distribution layer in the device package, and then the power is transferred from the re-distribution layer to a printed circuit board, typically through a ground signal ground (GSG) configuration implemented in a ball grid array. The signal/power is then routed through a grounded coplanar waveguide structure, transitioned to a microstrip structure, which then excites a radiator which is used to launch into a waveguide. This approach has the advantage of utilizing well established technology but also has the following disadvantages: (i) the requirement to produce controlled impedance structures on the host printed circuit board; (ii) the cost and supply chain complexity of utilizing a low loss PCB material on the host printed circuit board; and (iii) multiple sets of transition losses: MMIC to RDL, RDL to BGA, BGA to PCB, PCB to Waveguide, where these transition losses partially negate the benefit of utilizing a waveguide, particularly for short transmission line lengths.
The second transition approach that has been proposed is to launch directly from the package into the waveguide. An example description of this approach is provided on page 30 of the following document: http://www.ipcei-me.eu/wp-content/uploads/2020/11/4-Pack-Trends-for-mm-wave-Radar-Infineon-Maciej-Wojnowski.pdf. This approach negates the following disadvantages of the first approach: (i) the requirement to produce controlled impedance structures on the host printed circuit board; (ii) the cost and supply chain complexity of utilizing a low loss PCB material on the host printed circuit board; and (iii) a net reduction in Transition losses, namely BGA to PCB. The reduction of PCB cost and supply chain complexity is expected to be attractive to the developers of mmWave radar and communication systems.
In the design of mmWave radar or communication systems, antenna selection and design is a significant consideration. In radar systems, there are two primary-use cases: first, radar systems intended to operate over a long range; and second, radar systems required to operate over a shorter range, but with a wider coverage area. In the field of automotive sensors, these are typically referred to as Long Range Radars, which are utilized for functions like adaptive cruise control, and Corner Radars or Short Range Radars, which are used for functions like blind spot detection, lane change assist, or parking assistance.
A long range radar is typically expected to cover the lanes ahead of or behind the vehicle. Corner radars are used to supplement the coverage of the long range radar, with the aim of providing 360 degree coverage around the vehicle. It is also desirable to have redundancy in coverage, so a corner radar will typically try to cover a 120 degree azimuth field of view, while a long range radar may typically cover a 60-90 degree azimuth field of view. For reference, the elevation plane is typically oriented in the direction of the height of the vehicle, while the azimuth plane is perpendicular to the elevation plane. In the case where vehicles are expected to operate at a higher level of autonomy, for example SAE level 3 or level 4 autonomy, the vehicle may also employ mid range radars, which operate with an azimuth coverage between that of a corner radar and a long range radar. For vehicle total cost of ownership, it may also be desirable to produce corner radars which have enhanced range, thereby eliminating the need for the mid-range radar.
The antenna architecture is typically first selected for its field of view, and then for its bandwidth, though the type of antenna will also depend on the type of antenna feed. In printed circuit board based feed networks, the antenna is also typically formed on the PCB, and in waveguide structures, it is desirable to use a similar construction method to the way a waveguide is produced. Polarization is another consideration that designers use when selecting an antenna. Finally, side-lobe levels are significant in many radar and communication systems. For long range radar antennas, where the field of view (related to the azimuth half power beamwidth of the antenna) is smaller, a series-fed microstrip patch antenna is typically used. Parallel series-fed lines can be used to further reduce the field of view, increasing the gain of the antenna and subsequently the range of the radar system.
To achieve a wide field of view, either comb-line (sometimes referred to as side fed patch) or slot antennas are typically employed.
A substrate integrated waveguide (SIW) plus a slot antenna can also be employed with a printed circuit board feed network. A slot antenna will typically exhibit some of the widest field of views, but brings additional PCB fabrication complexity.
In waveguide-based feed networks, two fundamental antenna types are most often employed. For high gain applications, a waveguide fed horn will typically be used. This can provide both a high gain, and wide bandwidth (>15% fractional bandwidth). For wide field of view applications, a slot antenna is often used. The slot antenna formed in an air metal waveguide will exhibit bandwidth larger than its counterpart from a substrate integrated waveguide, but is smaller than desired (eg. 2 GHz at 79 GHz, when 4-5 GHz is desirable).
Bandwidth requirements are highly dependent on the application. For a Doppler effect radar system, two primary benefits can be derived from a wide bandwidth (eg. 4-5 Ghz): (i) a wide fractional bandwidth can be utilized to provide a high distance resolution (proportional to the speed of light divided by bandwidth), ie a 4 GHz bandwidth will provide 3.5 cm range resolution. This is most desirable when the radar is detecting an object that is close to the sensor. For example, whether a car is 1 meter or 1.05 meters away is a critical piece of information when performing parking assistance, but whether a car is 200 meters away or 200.05 meters away is not important when performing adaptive cruise control; and, (ii) a wide fractional bandwidth can also be used to provide the ability for a radar system to employ a smaller instantaneous bandwidth (ie 500 Mhz), but switch frequencies within that wider fractional bandwidth to avoid interference. As corner, or short range, radars provide a wider angular coverage, they are more susceptible to interference from an adjacent vehicle. Additionally, as the number of vehicles on the road employing corner radar is constantly increasing, the interference issue is constantly getting worse.
In summary, within the field of waveguide fed antennas applied to radar, a narrow field of view antenna can be produced with a large bandwidth, but the large bandwidth is not an important feature due to the application of the radar. In the application where a large (wide) bandwidth would be important, the narrow field of view of the horn antenna is not desirable. Therefore, in the field of waveguide fed radar antennas, there exists a performance gap which provides value to the market, but currently cannot be achieved cost effectively, the combination of a wide fractional bandwidth (eg. 4-5 Ghz at 79 Ghz) and a wide field of view (for example a half power azimuth beam width of 120 degrees).
Rogers Corporation has developed a technology to address the antenna issue, a specific embodiment of a dielectric resonator antenna. The dielectric resonator antenna invented by Rogers Corporation offers a combination of wide field of view and broad bandwidth that is desirable for corner radar applications. However, to date it has been utilized with a PCB based substrate integrated waveguide feed network, which has the above mentioned issues with insertion loss between the MMIC and the antenna. While it is certainly possible, and in some cases desirable, to combine the dielectric resonator antenna with a waveguide feed network, the added cost of both systems may preclude its use from some high volume applications. So, there exists an unmet need for a waveguide fed wide field of view, wide band width antenna which can be acquired at a competitive price with respect to the waveguide plus slot antenna alone.
Though the above background focuses on automotive radar, scenarios can be envisioned where these requirements would translate to non-automotive applications, for example, a set of radars utilized in a factory automation scenario (at 60 Ghz) could also experience a similar set of challenges.
Regarding waveguide fabrication, there are two primary approaches being utilized to produce waveguide plus antenna(s) for high volume radar applications today: (i) multilayer molded traditional waveguides; and (ii) bandgap waveguides. Evaluating the relative benefits of both systems is largely an exercise in comparing complexity and therefore cost.
Traditional waveguides are formed by molding multiple layers of plastic, metallizing those layers, and bonding the layers together with an electrically conductive adhesive, or in another way to provide a consistent and reliable electrical connection from one layer to another. An example of such a stack up can be found in U.S. Pat. Publ. 2020/0313304. The complexity in this system is derived from the number of metalized plastic layers (up to 7 for complex structures, 2-3 for simple structures), and the need to bond the layers together with a robust electrical connection between layers.
A bandgap waveguide utilizes a specialized structure to form the interior walls of the waveguide. This is referred to as an “electromagnetic bandgap structure”, or “artificial magnetic conductor”. The principal benefit of this structure is that a robust electrical connection between the top and bottom of the waveguide is not required in this structure, reducing the complexity of the waveguide assembly. This benefit has shown to have market value.
However, this structure could introduce some additional complexity into the mold tolerance requirements, and in the typical construction requires four metal layers. The complexity of fabrication grows in a non-linear fashion as the number of layers in the structure increases, and the cost of materials also increases with the number of metal layers. Therefore, there exists an unserved need in the market place for a solution with: (i) a feed network which can be excited from an antenna-in-package, or similar MMIC package, excitation; (ii) provision for a low insertion loss, for example 0.25-0.5 dB/in at 79 Ghz; (iii) capability of being fabricated with a minimum of cost and complexity; (iv) potential to offer an antenna solution which provides a wide field of view and large bandwidth, for example, 120 degrees half power beamwidth, and a 5 Ghz bandwidth with a center frequency of 78.5 GHz; (v) alternatively, a system which offers the first three points with reduced cost and complexity and provides a high gain, with an optionally broad bandwidth, which would be desirable for other applications such as long range radar; (vi) a feed network which can be excited from a PCB, or form an antenna-in-package, or similar MMIC, excitation; (vii) low insertion loss, for example 0.25-0.5 dB/in at 79 GHz; (viii) capability of being fabricated with only one metalized layer, and potentially one dielectric layer (optionally metallized plastic only, dielectric in preferred embodiment); (ix) an antenna that offers a solution which provides a wide field of view and large bandwidth, for example, 120 degrees half power beamwidth, and a 5 Ghz bandwidth with a center frequency of 78.5 GHz; and, (x) alternatively, a system that can offer high gain and optionally large bandwidth.
Some dielectric resonator antennas may be tailored to desired patterns over large bandwidth, but have substantial losses in gain when incorporated in antenna systems due to loss in the required feed structures and transitions. Some molded traditional waveguide antennas may be incorporated into antenna systems that minimize losses in the feed and transition for high gain, but these offer a smaller useable bandwidth (i.e. <3 GHz).
While existing antennas may be suitable for their intended purpose, there remains a need for a pattern tailorable, high gain, antenna system (with minimal feed and transition losses) that can be tailored for high gain with controlled shape of antenna pattern versus angle over a large bandwidth (i.e. ≥4 GHz) up to millimeter wave frequency bands.
The following publications may be considered as useful background art: U.S. Pat. Nos. 3,015,100; 6,043,787; and, U.S. Pat. Publ. 2020/0313304.
An embodiment includes an open waveguide antenna as defined by the appended independent claims. Further advantageous modifications of the open waveguide antenna are defined by the appended dependent claims.
An embodiment includes a waveguide antenna system, having: an electromagnetic, EM, transition portion having a transition region having a signal feed interface and an open waveguide section, the EM transition portion configured to couple EM energy from the signal feed interface to a guided waveguide mode of EM energy to the open waveguide section via the transition region; and a leaky waveguide antenna portion configured and disposed to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support a transfer of electromagnetic energy from a signal feed structure to the leaky waveguide antenna portion.
An embodiment includes a waveguide antenna system, having: a plurality of the waveguide antenna system as disclosed herein above configured for antenna-on-package applications.
An embodiment includes a waveguide antenna system, having: a plurality of the waveguide antenna system as disclosed herein above configured for patch-on-printed-circuit-board applications.
An embodiment includes an open waveguide signal feed system, having: a printed circuit board having a signal feed and a signal feed output; an open waveguide having a signal feed input port; a transition region disposed between and in signal communication with the signal feed output and the signal feed input port; wherein the signal feed comprises a microstrip, a coplanar waveguide, or a stripline; wherein the signal feed output comprises a patch or a probe.
An embodiment includes an open waveguide section, having: at least one bend in a trough waveguide, the at least one bend being in a direction of propagation of an electromagnetic wave in the trough waveguide, the trough waveguide having a trough having first and second opposing sidewalls, a septum disposed therebetween, a first base disposed between the first sidewall and the septum, and a second base disposed between the septum and the second sidewall, wherein all surfaces internal to the trough of at least the first sidewall, the second sidewall, the septum, the first base, and the second base, are electrically conductive; and an electromagnetic radiation suppressor strategically configured and disposed to suppress undesirable electromagnetic radiation that may emanate from the at least one bend in the absence of such electromagnetic radiation suppressor.
An embodiment includes an open waveguide antenna, having: a trough having first and second opposing sidewalls, a septum disposed therebetween, a first base disposed between the first sidewall and the septum, and a second base disposed between the septum and the second sidewall; wherein one or more of surfaces internal to the trough of at least the first sidewall, the second sidewall, the septum, the first base, and the second base, are electrically conductive; wherein the first base has a first sequence of undulations that are longitudinally disposed along a length of the trough; wherein the first sequence of undulations alternatively and sequentially follow a first curved path and a second curved path, the second curved path being asymmetric to the first curved path; wherein the second base has a second sequence of undulations that are longitudinally disposed along the length of the trough; wherein the second sequence of undulations alternatively and sequentially follow the second curved path and the first curved path; wherein the first curved path and the second curved path alternate from one side of the septum to the other side of the septum along the length of the trough.
The above features and advantages and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.
Referring to the exemplary non-limiting drawings wherein like elements are numbered or illustrated alike in the accompanying Figures:
One skilled in the art will understand that the drawings, further described herein below, are for illustration purposes only. It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions or scale of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements, or analogous elements may not be repetitively enumerated in all figures where it will be appreciated and understood that such enumeration where absent is inherently disclosed.
As used herein, the phrase “embodiment” means “embodiment disclosed and/or illustrated herein”, which may not necessarily encompass a specific embodiment of an invention in accordance with the appended claims, but nonetheless is provided herein as being useful for a complete understanding of an invention in accordance with the appended claims.
Although the following detailed description contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the appended claims. For example, where described features may not be mutually exclusive of and with respect to other described features, such combinations of non-mutually exclusive features are considered to be inherently disclosed herein. Additionally, common features may be commonly illustrated in the various figures but may not be specifically enumerated in all figures for simplicity, but would be recognized by one skilled in the art as being an explicitly disclosed feature even though it may not be enumerated in a particular figure. Accordingly, the following example embodiments are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention disclosed herein.
An embodiment, as shown and described by the various figures and accompanying text, provides an antenna system that can be adapted from a patch feed (i.e. on an antenna-in-package or circuit board structure) through a transition into an open waveguide antenna structure with minimal losses throughout the structure, allowing for tailorable, high gain antenna systems that can be used over a large bandwidth (i.e. ≥4 GHz) and up to millimeter wave frequencies.
For simplicity of integration, and illustration herein, the feed structure used may be a patch, but other feed structures such as probes (e.g., a coax line, a plated hole in a printed circuit board, or the like), loops, or apertures, are also possible, and contemplated herein. The patch structure may be ideally part of an antenna chip in package to minimize distances, allow for miniaturization, and reduce cost, by avoiding an additional RF layer. However, patches may also be formed on any type of substrate layer, including a buildup layer, or a layer in a printed circuit board.
The open waveguide antenna can be specifically designed to allow for desired antenna radiation patterns. For example, a wide field of view can be obtained, as is often useful in a corner radar application for automotive safety systems. In other cases, it may be desired to achieve maximum gain over a narrower field of view, such as in forward facing long distance automotive radar applications. The variables of the open waveguide antenna that can be adjusted to achieve the desired pattern may include size of the open radiating aperture, angle of radiating aperture, baseplane undulations, or dielectric discontinuities creating radiation. Furthermore, a dielectric cover or lens structure may be added over the metal open waveguide to further optimize the pattern. Where multiple antenna channels are needed, such as in the aforementioned corner radar application, multiple open waveguide antenna structures can be combined into one piece for ease of manufacture, with individual open waveguide antenna elements being separated by a distance 0.5 to 10 times the wavelength of the signals being processed.
Various features can be included in the open waveguide antenna design that facilitate manufacturing while maintaining the same excellent RF performance. These include “shelling” of the part to reduce material consumption and warpage, recesses and positive features to avoid sticking during metallization by electroplating, or other processes, as well as draft angles and convenient parting line locations to facilitate part removal.
Manufacturing methods for creating the single channel or multiple channel open waveguide antenna structure may be accomplished through a variety of methods, including metal die casting, injection molding of dielectric followed by surface metallization, and extrusion followed by singulating and surface metallization.
The transition from the feed structure to the open waveguide antenna is designed such that losses are minimized. Suitable transition structures for achieving this purpose include ridge waveguide with patch feed, rectangular waveguide with patch feed, open waveguide with patch feed or probe feed, coplanar waveguides and others.
Another embodiment, as shown and described by the various figures and accompanying text, provides a trough waveguide antenna (TWGA) useful, in one example, for automotive radar applications. The TWGA combines the function of a trough waveguide with the function of an electromagnetic (EM) radiator (antenna). Trough waveguides have symmetry between the left and right sides of their dividing septum, and operate primarily as a guided-mode EM transmission element. Comparatively, trough waveguide antennas have asymmetry between the left and right sides of their dividing septum, and necessarily have at least a partial open top, which enables them to operate as both an EM transmission element and as an EM radiating element. As used herein, the phrase “open top” means a top, cover, or ceiling, of the TWGA that is open to, or allows passage of, EM radiation energy. As such, an open top does not preclude the presence of a dielectric cover over the TWGA. A monolithic microwave integrated circuit (MMIC) may be used to bring a signal to an input port of the TWGA.
While reference is made herein to a trough waveguide antenna, it will be appreciated that a more generic term for describing the same is to refer to an open waveguide antenna, where the aforementioned trough waveguide antenna is a specific subset of an open waveguide antenna structure.
As used herein, the term monolithic means a structure integrally formed from a single material composition.
While embodiments illustrated and described herein depict an example TWGA having a particular three-dimensional (3D) geometry, it will be appreciated that this geometry is merely one example of many geometries that may be employed in the design of a TWGA depending on the desired performance characteristics (operating frequency, bandwidth, gain, return loss, radiation pattern, etc.) of the TWGA. It will also be appreciated that the disclosed geometry may be modified without departing from a scope of the invention. As such, the disclosure herein applies to any TWGA design that falls within the ambit of the appended claims, and any 3D geometry that falls within the ambit of the disclosure herein, and is suitable for a purpose disclosed herein, is contemplated and considered to be complementary to the particular embodiments disclosed herein.
Reference is now made to
In an embodiment, the TWG 1000 (more generally herein referred to as an open waveguide) has: a trough 1010 having first and second opposing sidewalls 1020, 1030, a septum 1040 disposed between the first and second sidewalls 1020, 1030, a first base 1050 disposed between the first sidewall 1020 and the septum 1040, and a second base 1060 disposed between the septum 1040 and the second sidewall 1030; wherein all surfaces 1070 internal to the trough 1010 of at least the first sidewall 1020, the second sidewall 1030, the septum 1040, the first base 1050, and the second base 1060, are electrically conductive. In an embodiment, the septum 1040 extends upward from the first base 1050 and the second base 1060, as observed from the perspective of
In an embodiment, the TWGA 2000 (more generally herein referred to as an open waveguide antenna) has: a trough 2010 having first and second opposing sidewalls 2020, 2030, a septum 2040 disposed between the first and second sidewalls 2020, 2030, a first base 2050 disposed between the first sidewall 2020 and the septum 2040, and a second base 2060 disposed between the septum 2040 and the second sidewall 2030; wherein all surfaces 2070 internal to the trough 2010 of at least the first sidewall 2020, the second sidewall 2030, the septum 2040, the first base 2050, and the second base 2060, are electrically conductive; wherein the first base 2050 has a first sequence of undulations 2052 that are longitudinally disposed along a length of the trough 2010; wherein the first sequence of undulations 2052 alternatively (high-to-low in
In an embodiment, the septum 2040 extends upward from the first base 2050 and the second base 2060, as observed from the perspective of
In an embodiment, at least a portion of the first sequence of undulations 2052 includes a dielectric material and/or at least a portion of the second sequence of undulations 2062 includes a dielectric material. By strategically placing dielectric material as part of the undulations 2052, 2062, controlled radiation from the leaky TWGA 2000 is further achievable.
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A guided wave, by definition, does not radiate and can be obtained in a myriad of ways. For example, a rectangular dielectric waveguide that confines the energy within its dielectric, or a rectangular metallic waveguide that confines the energy within its metallic walls. An open waveguide is simply a metallic structure that guides waves and is open at one or more of its ends or sides. The only requirement for an open type of waveguide 1000 is for it to support a guided waveguide mode. A groove waveguide 1015 having dimensions a1, a2, and b is an example of an open type of waveguide, as depicted in
An open waveguide 1000 is a natural guiding structure to electromagnetically couple with and feed a leaky waveguide antenna 2000. A leaky waveguide antenna works by properly designing the amount of leakage (alpha) across the antenna along with the phase response (beta) (see alpha, α, and beta, β, in
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Aspect 1. A waveguide antenna system, comprising: an electromagnetic, EM, transition portion comprising a transition region having a signal feed interface and an open waveguide section, the EM transition portion configured to couple EM energy from the signal feed interface to a guided waveguide mode of EM energy to the open waveguide section via the transition region; and a leaky waveguide antenna portion configured and disposed to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support a transfer of electromagnetic energy from a signal feed structure to the leaky waveguide antenna portion.
Aspect 2. The waveguide antenna system of Aspect 1, wherein: the EM transition portion is configured to support a transfer of electromagnetic energy from a planar signal feed structure to the leaky waveguide antenna portion.
Aspect 3. The waveguide antenna system of any one of Aspects 1 to 2, wherein: the open waveguide section comprises an open trough waveguide.
Aspect 4. The waveguide antenna system of any one of Aspects 1 to 2, wherein: the open waveguide section comprises an open groove waveguide.
Aspect 5. The waveguide antenna system of any one of Aspects 1 to 4, wherein: the open waveguide section is absent of discontinuities along its respective length; the leaky waveguide antenna portion comprises substantial discontinuities along its respective length; and, the open waveguide section is electromagnetically coupled to the leaky waveguide antenna portion with an electromagnetic coupling therebetween where a change in discontinuities transition from the absence of discontinuities of the open waveguide section to the substantial discontinuities of the leaky waveguide antenna portion.
Aspect 6. A waveguide antenna system, comprising: a plurality of the waveguide antenna system of any one of Aspects 1 to 5 configured for antenna-on-package applications.
Aspect 7. A waveguide antenna system, comprising: a plurality of the waveguide antenna system of any one of Aspects 1 to 5 configured for patch-on-printed-circuit-board applications.
Aspect 8. The waveguide antenna system of any one of Aspects 6 to 7, wherein: in a transmit mode and configuration, each open waveguide section is disposed and configured to receive electromagnetic energy from an antenna-on-package component, or a patch-on-printed-circuit-board component, and deliver the electromagnetic energy to a corresponding leaky waveguide antenna portion; and in a receive mode and configuration, each open waveguide section is disposed and configured to receive electromagnetic energy from a corresponding leaky waveguide antenna portion and deliver the electromagnetic energy to an antenna-on-package component, or a patch-on-printed-circuit-board component.
Aspect 9. An open waveguide signal feed system, comprising: a printed circuit board having a signal feed and a signal feed output; an open waveguide having a signal feed input port; a transition region disposed between and in signal communication with the signal feed output and the signal feed input port; wherein the signal feed comprises a microstrip, a coplanar waveguide, or a stripline; wherein the signal feed output comprises a patch or a probe.
Aspect 10. The open waveguide signal feed system of Aspect 9, wherein: the transition region comprises an enclosed waveguide.
Aspect 11. The open waveguide signal feed system of Aspect 9, wherein: the transition region comprises an edge feed between the signal feed output and the signal feed input port.
Aspect 12. The open waveguide signal feed system of Aspect 9, wherein: the transition region comprises an aperture at the signal feed output that is electromagnetically coupled directly to the signal feed input port.
Aspect 13. An open waveguide section, comprising: at least one bend in a trough waveguide, the at least one bend being in a direction of propagation of an electromagnetic wave in the trough waveguide, the trough waveguide comprising a trough having first and second opposing sidewalls, a septum disposed therebetween, a first base disposed between the first sidewall and the septum, and a second base disposed between the septum and the second sidewall, wherein all surfaces internal to the trough of at least the first sidewall, the second sidewall, the septum, the first base, and the second base, are electrically conductive; and an electromagnetic radiation suppressor strategically configured and disposed to suppress undesirable electromagnetic radiation that may emanate from the at least one bend in the absence of such electromagnetic radiation suppressor.
Aspect 14. The open waveguide section of Aspect 13, wherein: the electromagnetic radiation suppressor comprises an electromagnetic radiation absorbing material disposed over an upper open end of the at least one bend of the trough waveguide.
Aspect 15. The open waveguide section of Aspect 13, wherein: the electromagnetic radiation suppressor comprises an electromagnetic choking mechanism disposed within the at least one bend of the trough waveguide.
Aspect 16. The open waveguide section of Aspect 15, wherein: the electromagnetic choking mechanism comprises at least one quarter-wavelength trench cut into each of the first and second sidewalls of the trough.
Aspect 17. The open waveguide section of Aspect 16, wherein: the at least one quarter-wavelength trench comprises at least one pair of symmetrically arranged trenches disposed in the first and second sidewalls of the trough.
Aspect 18. The open waveguide section of any one of Aspects 16 to 17, wherein: the at least one quarter-wavelength trench comprises a horizontal portion and a contiguous vertical portion.
Aspect 19. The open waveguide section of any one of Aspects 16 to 17, wherein: the first and second sidewalls of the trough have angled sidewalls, and the at least one quarter-wavelength trench is formed in each corresponding angled sidewall.
Aspect 20. The open waveguide section of Aspect 15, wherein: the electromagnetic choking mechanism comprises an electromagnetic reflector having Total Internal Reflection, TIR, properties in the form of a cover disposed over the upper open end of the at least one bend of the trough waveguide, and extending across the at least one bend of the trough from the first sidewall to the second sidewall, the TIR reflector being comprised of a dielectric material having a varying dielectric constant along a direction normal to the cover which produces total internal reflection.
Aspect 21. The open waveguide section of Aspect 15, wherein: the electromagnetic choking mechanism comprises a dielectric medium disposed over the upper open end of the at least one bend of the trough waveguide, and extending across the at least one bend of the trough from the first sidewall to the second sidewall, the dielectric medium being comprised of a dielectric material having a dielectric constant greater than 6.
Aspect 22. The open waveguide section of Aspect 13, wherein: the electromagnetic radiation suppressor comprises a modified septum having a reduced height within the at least one bend that is lower that an original height of the septum outside of the at least one bend.
Aspect 23. The open waveguide section of Aspect 22, wherein: the modified septum gradually tapers down from the original height to the reduced height.
Aspect 24. The open waveguide section of Aspect 13, wherein: the electromagnetic radiation suppressor comprises a modified inner surface of the trough within the at least one bend that is configured to affect the phase velocity and/or waveguide impedance such that the phase velocity and/or waveguide impedance are constant or substantially constant along a path length of the at least one bend.
Aspect 25. The open waveguide section of Aspect 24, wherein: the modified inner surface of the trough comprises a tapered bottom surface of the waveguide trough between the septum and at least one of the first sidewall and the second sidewall.
Aspect 26. The open waveguide section of Aspect 25, wherein: the tapered bottom surface is tapered upward from the septum toward the outside wall on an outside of the at least one bend.
Aspect 27. The open waveguide section of Aspect 24, wherein: the modified inner surface of the trough comprises a height differential between the first base of the trough and the second base of the trough.
Aspect 28. The open waveguide section of Aspect 24, wherein the trough comprises a first trough portion between the first sidewall and the septum, and a second trough portion between the second sidewall and the septum, wherein the first trough portion is disposed on an inside curvature of the at least one bend and the second trough portion is disposed on an outside curvature of the at least one bend, and further wherein: the modified inner surface of the trough comprises a width differential between the first trough portion and the second trough portion.
Aspect 29. The open waveguide section of Aspect 24, wherein: the modified inner surface of the trough comprises a lateral positioning of the septum within the at least one bend that is asymmetrical with respect to the first and second sidewall s.
Aspect 30. The open waveguide section of Aspect 24, wherein: the modified inner surface of the trough comprises a thickness of the septum within the at least one bend that is different from a thickness of the septum outside of the at least one bend.
Aspect 31. The open waveguide section of Aspect 24, wherein: the first sidewall is an inside sidewall of the at least one bend; the second sidewall is an outside sidewall of the at least one bend; the first base has a first width between the first sidewall and the septum that defines a first trough portion disposed on an inside curvature of the at least one bend; the second base has a second width between the septum and the second sidewall that defines a second trough portion disposed on an outside curvature of the at least one bend; and the first width is greater than the second width.
Aspect 32. The open waveguide section of Aspect 31, wherein: a cross-section of the second trough portion inside of the at least one bend has a width that is less than the corresponding cross-section width outside of the at least one bend, which serves to increase the capacitance of the second trough portion inside of the at least one bend.
Aspect 33. The open waveguide section of any one of Aspects 31 to 32, wherein: a cross-section of the first trough portion inside of the at least one bend has a width that is greater than the corresponding cross-section width outside of the at least one bend, which serves to decrease the capacitance of the first trough portion inside of the at least one bend.
Aspect 34. The open waveguide section of Aspect 32, wherein: the cross-section width of the second trough portion inside of the at least one bend has a width dimension as low as 200 micrometers or lower.
Aspect 35. The open waveguide section of Aspect 33, wherein: the cross-section width of the first trough portion inside of the at least one bend has width dimension no greater than one-half of a wavelength of an operating frequency of the open waveguide section inside of the at least one bend.
Aspect 36. The open waveguide section of Aspect 24, wherein: the trough waveguide has a first depth to the first base and to the second base, outside of a curvature of the at least one bend, and a second depth to the first base and to the second base, inside of the curvature of the at least one bend; and, the first depth outside of the curvature of the bend is greater than the second depth inside of the curvature of the bend.
Aspect 37. The open waveguide section of any one of Aspects 24 and 36, wherein the trough comprises a first trough portion between the first sidewall and the septum, and a second trough portion between the second sidewall and the septum, and further wherein: a cross-section of the second trough portion inside of the at least one bend has a depth that is less than the corresponding cross-section depth outside of the at least one bend, which serves to increase the impedance of the second trough portion inside of the at least one bend, and to increase the phase velocity of an electromagnetic wave, when present, propagating through the second trough portion.
Aspect 38. The open waveguide section of Aspect 37, wherein: a cross-section of the first trough portion inside of the at least one bend has a depth that is greater than the corresponding cross-section depth outside of the at least one bend, which serves to decrease the impedance of the first trough portion inside of the at least one bend, and to decrease the phase velocity of an electromagnetic wave, when present, propagating through the first trough portion.
Aspect 39. The open waveguide section of Aspect 37, wherein: the cross-section depth of the second trough portion is at least as deep as the septum is high.
Aspect 40. The open waveguide section of Aspect 38, wherein: the cross-section depth of the first trough portion inside of the at least one bend with respect to the cross-section depth of the first trough portion outside of the at least one bend increases by at most one-quarter of a wavelength of an operating frequency of the open waveguide section inside of the at least one bend.
Aspect 41. The open waveguide section of Aspect 24, wherein: the septum has a first wall thickness outside of the at least one bend, and a second wall thickness inside the at least one bend; and the first wall thickness is less than the second wall thickness.
Aspect 42. An open waveguide antenna, comprising: a trough having first and second opposing sidewalls, a septum disposed therebetween, a first base disposed between the first sidewall and the septum, and a second base disposed between the septum and the second sidewall; wherein one or more of surfaces internal to the trough of at least the first sidewall, the second sidewall, the septum, the first base, and the second base, are electrically conductive; wherein the first base has a first sequence of undulations that are longitudinally disposed along a length of the trough; wherein the first sequence of undulations alternatively and sequentially follow a first curved path and a second curved path, the second curved path being asymmetric to the first curved path; wherein the second base has a second sequence of undulations that are longitudinally disposed along the length of the trough; wherein the second sequence of undulations alternatively and sequentially follow the second curved path and the first curved path; wherein the first curved path and the second curved path alternate from one side of the septum to the other side of the septum along the length of the trough.
Aspect 43. The open waveguide antenna of Aspect 42, wherein: all surfaces internal to the trough of the first base and the second base are electrically conductive.
Aspect 44. The open waveguide antenna of Aspect 42, wherein: at least a portion of the first sequence of undulations comprises a dielectric material.
Aspect 45. The open waveguide antenna of Aspect 42, wherein: at least a portion of the second sequence of undulations comprises a dielectric material.
Aspect 46. The open waveguide antenna of any one of Aspects 42 to 45, wherein: the trough is a monolithic non-electrically conductive construct with the electrically conductive surfaces formed thereon.
Aspect 47. The open waveguide antenna of any one of Aspects 42 to 46, wherein: the septum extends upward from the first and second bases.
Aspect 48. The open waveguide antenna of any one of Aspects 42 to 47, wherein: exposed surfaces of the first sidewall, the second sidewall, and the septum, are not parallel to each other along the length of the trough.
Aspect 49. The open waveguide antenna of any one of Aspects 42 to 48, wherein: the septum has a height that is less than a height of either the first sidewall or the second sidewall.
Aspect 50. The open waveguide antenna of any one of Aspects 42 to 49, wherein: the septum is centrally disposed between the first sidewall and the second sidewall.
Aspect 51. The open waveguide antenna of any one of Aspects 42 to 50, wherein: the first sequence of undulations and the second sequence of undulations are asymmetric about the septum.
Aspect 52. The open waveguide antenna of any one of Aspects 42 to 51, wherein: the first sequence of undulations alternate in elevation between the first curved path and the second curved path along the length of the trough.
Aspect 53. The open waveguide antenna of any one of Aspects 42 to 52, wherein: the second sequence of undulations alternate in elevation between the second curved path and the first curved path along the length of the trough.
Aspect 54. The open waveguide antenna of any one of Aspects 42 to 53, wherein: as observed in a sideview of the trough, the first curved path is a first waveform with alternating peaks and valleys, the first waveform being a composite of a smooth waveform multiplied by a square wave.
Aspect 55. The open waveguide antenna of Aspect 54, wherein: as observed in a sideview of the conductive trough, the second curved path is a second waveform with alternating peaks and valleys, the second waveform being a composite of a smooth waveform multiplied by a square wave.
Aspect 56. The open waveguide antenna of Aspect 55, wherein: the second smooth waveform and the first smooth waveform have different elevations in both peaks and valleys at all points between and inboard of the ends of the trough.
Aspect 57. The open waveguide antenna of any one of Aspects 42 to 56, further comprising: a dielectric cover disposed over, covering, and extending at least a portion of the length of the trough, and extending across the trough from the first sidewall to the second sidewall, the dielectric cover comprised of a dielectric material having a dielectric constant greater than one.
Aspect 58. The open waveguide antenna of Aspect 57, wherein: an upper outer surface of the dielectric cover has a longitudinal indentation that extends along the length of the trough.
Aspect 59. The open waveguide antenna of Aspect 58, wherein: the longitudinal indentation is centrally disposed along the length of the trough.
Aspect 60. The open waveguide antenna of any one of Aspects 58 to 59, wherein: the longitudinal indentation has a concave cross section profile.
Aspect 61. The open waveguide antenna of Aspect 60, wherein: the concave cross section profile is representable by a polynomial curve.
Aspect 62. The open waveguide antenna of Aspect 57, wherein: an upper outer surface of the dielectric cover has a longitudinal protrusion that extends along the length of the trough.
Aspect 63. The open waveguide antenna of Aspect 62, wherein: the longitudinal protrusion is centrally disposed along the length of the trough.
Aspect 64. The open waveguide antenna of any one of Aspects 62 to 63, wherein: the longitudinal protrusion has a convex cross section profile.
Aspect 65. The open waveguide antenna of Aspect 64, wherein: the convex cross section profile is representable by a polynomial curve.
Aspect 66. The open waveguide antenna of Aspect 57, wherein: a lower inner surface of the dielectric cover has a longitudinal indentation that extends along the length of the trough.
Aspect 67. The open waveguide antenna of Aspect 66, wherein: the longitudinal indentation is centrally disposed along the length of the trough.
Aspect 68. The open waveguide antenna of any one of Aspects 66 to 67, wherein: the longitudinal indentation has a concave cross section profile.
Aspect 69. The open waveguide antenna of Aspect 68, wherein: the concave cross section profile is representable by a polynomial curve.
Aspect 70. The open waveguide antenna of Aspect 57, wherein: a lower inner surface of the dielectric cover has a longitudinal protrusion that extends along the length of the trough.
Aspect 71. The open waveguide antenna of Aspect 70, wherein: the longitudinal protrusion is centrally disposed along the length of the trough.
Aspect 72. The open waveguide antenna of any one of Aspects 70 to 71, wherein: the longitudinal protrusion has a convex cross section profile.
Aspect 73. The open waveguide antenna of Aspect 72, wherein: the convex cross section profile is representable by a polynomial curve.
Aspect 74. The open waveguide antenna of any one of Aspects 42 to 73 having a moldable construct, wherein: the moldable construct comprises one or more of: (i) positive fabrication features that do not allow flat surface features to stick during a barrel electroplating process; (ii) one or more screw locations incorporated in the construct; (iii) a shelled construct to reduce material consumption and warpage; (iv) integrally formed recesses to reduce sticking tendency during electroplating; (v) a molding draft angle equal to or greater than 2-degrees provided on the top side; (vi) a molding draft angle of equal to or greater than 4-degrees provided on the bottom side; and, (vii) a molding parting line located proximate the bottom face.
Aspect 75. The open waveguide antenna of any one of Aspects 42 to 73, wherein: the trough is a diecast construct.
Aspect 76. The open waveguide antenna of any one of Aspects 42 to 73, wherein: the trough is an injection molded plastic construct.
Aspect 77. The open waveguide antenna of Aspect 76, wherein: the injection molded plastic construct is metallized to provide electrically conductive surfaces thereon.
Aspect 78. An open waveguide antenna system comprising the open waveguide antenna of any one of Aspects 42 to 77, the open waveguide antenna system further comprising: a signal feed port disposed at one end of the trough; and an electrical short circuit disposed at a second opposing end of the trough.
Aspect 79. The open waveguide antenna system of Aspect 78, further comprising: an electrically conductive surface disposed proximate an upper end of the trough; wherein the electrical short circuit is electrically connected to the electrically conductive surface; and wherein the electrically conductive surface has an aperture configured and disposed to expose the upper end of the trough for electromagnetic coupling therewith.
Aspect 80. The open waveguide antenna system of any one of Aspects 78 to 79, wherein: a patch-to-trough guide transition is configured such that the patch E-polarization is parallel with the septum.
Aspect 81. The open waveguide antenna system of any one of Aspects 78 to 79, wherein: a patch-to-trough guide transition is configured such that the patch E-polarization is perpendicular to the septum.
Aspect 82. A multi-channel open waveguide antenna, comprising: a plurality of the open waveguide antenna of any one of Aspects 42 to 63 arranged in a side-by-side configuration with a center-to-center spacing of adjacent troughs being equal to or greater than λ/2, and equal to or less than 10 times λ, where λ is a wavelength at an operational frequency of the multi-channel open waveguide antenna.
Aspect 83. The multi-channel open waveguide antenna of Aspect 82, wherein: the side-by-side configuration is a multi-monolithic construct.
Aspect 84. The multi-channel open waveguide antenna of any one of Aspects 82 to 83, wherein: the side-by-side configuration comprises a plurality of receiver channels and a plurality of transmitter channels.
Aspect 85. The multi-channel open waveguide antenna of Aspect 84, wherein: the plurality of receiver channels comprises at least 4 receiver channels.
Aspect 86. The multi-channel open waveguide antenna of Aspect 84, wherein: the plurality of transmitter channels comprises at least 3 transmitter channels.
Aspect 87. An open waveguide antenna system, comprising: a signal feed; an EM transition portion comprising a signal feed interface disposed at a first end of the EM transition portion and in EM communication with the signal feed, and an open waveguide section having a second end opposing the first end; and, an open waveguide antenna according to any one of Aspects 42 to 61, disposed in EM communication with the second end of the EM transition portion; wherein the EM transition portion is configured to couple EM energy from the signal feed to the signal feed interface to a guided waveguide mode of EM energy to the open waveguide section and to the open waveguide antenna.
Aspect 88. The open waveguide antenna system of Aspect 87, wherein: the signal feed comprises any one of: an antenna-in-package; a circuit board structure; a patch; a signal probe; a signal loop; and, a signal aperture.
Aspect 89. An open waveguide antenna system, comprising: an antenna on package; an open waveguide antenna according to any one of Aspects 42 to 61; an EM transition disposed in EM signal communication with and between the antenna on package and the open waveguide antenna.
Aspect 90. The open waveguide antenna system of Aspect 89, wherein: the EM transition comprises a ridge waveguide.
Aspect 91. The open waveguide antenna system of Aspect 89, wherein: the EM transition comprises a rectangular waveguide.
Aspect 92. The open waveguide antenna system of Aspect 89, wherein: the EM transition comprises a waveguide bend.
Some embodiments disclosed herein may have one or more of the following advantages: simultaneously achieving high gain, with minimal feed and transition losses; ability to tailor a given antenna pattern and high bandwidth; less sensitivity to small manufacturing variations than prior art DRA-with-dielectric-waveguide systems; and, a highly efficient antenna system formed by the strategic merging of an open waveguide section and a leaky waveguide antenna portion resulting in an antenna system applicable for modern multiple input multiple output (MIMO) automotive radar antennas.
As used herein, the phrase “equal to about” is intended to account for manufacturing tolerances and/or insubstantial deviations from a nominal value that do not detract from a purpose disclosed herein and falling within a scope of the appended claims.
While certain combinations of individual features have been described and illustrated herein, it will be appreciated that these certain combinations of features are for illustration purposes only and that any combination of any of such individual features may be employed in accordance with an embodiment, whether or not such combination is explicitly illustrated, and consistent with the disclosure herein. Any and all such combinations of features as disclosed herein are contemplated herein, are considered to be within the understanding of one skilled in the art when considering the application as a whole, and are considered to be within the scope of the invention disclosed herein, as long as they fall within the scope of the invention defined by the appended claims, in a manner that would be understood by one skilled in the art.
While an invention has been described herein with reference to example embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the claims. Many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment or embodiments disclosed herein as the best or only mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In the drawings and the description, there have been disclosed example embodiments and, although specific terms and/or dimensions may have been employed, they are unless otherwise stated used in a generic, exemplary and/or descriptive sense only and not for purposes of limitation, the scope of the claims therefore not being so limited. When an element such as a layer, film, region, substrate, or other described feature is referred to as being “on” or in “engagement with” another element, it can be directly on or engaged with the other element, or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or “directly engaged with” another element, there are no intervening elements present. The use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. The use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The use of the terms “top”, “bottom”, “up”, “down”, “left”, “right”, “front”, “back”, etc., or any reference to orientation, do not denote a limitation of structure, as the structure may be viewed from more than one orientation, but rather denote a relative structural relationship between one or more of the associated features as disclosed herein. The term “comprising” as used herein does not exclude the possible inclusion of one or more additional features. And, any background information provided herein is provided to reveal information believed by the applicant to be of possible relevance to the invention disclosed herein. No admission is necessarily intended, nor should be construed, that any of such background information constitutes prior art against an embodiment of the invention disclosed herein.
This application claims the benefit of U.S. Provisional Application Ser. No. 63/244,018, filed Sep. 14, 2021, and claims the benefit of U.S. Provisional Application Ser. No. 63/286,839, filed Dec. 7, 2021, both of which are incorporated herein by reference in their entireties.
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| Number | Date | Country | |
|---|---|---|---|
| 20230085413 A1 | Mar 2023 | US |
| Number | Date | Country | |
|---|---|---|---|
| 63286839 | Dec 2021 | US | |
| 63244018 | Sep 2021 | US |
