Embodiments disclosed herein are related to wireless communication; more particularly, embodiments disclosed herein are related to unit cell placement and frequency compensation.
Flat-panel antennas have become more prevalent in satellite communication systems in recent years. Of these flat-panel antennas, electronically-scanned antennas such as metasurface antennas have emerged as a new technology for generating steered, directive beams from a lightweight, low-cost, and planar physical platform. Metasurface antennas may comprise metamaterial antenna elements that can selectively couple energy from a feed wave to produce beams that may be controlled for use in communication. These antennas are capable of achieving comparable performance to phased array antennas from an inexpensive and easy-to-manufacture hardware platform, and are also being used in in-vehicle solutions.
Some flat-panel electronically-steerable metamaterial antennas having radio-frequency (RF) radiating unit cells that include devices to tune the RF radiating unit cells. In some implementations, varactor diodes are used to tune the RF radiating unit cells.
Antennas having iris and/or cell rotation and/or with frequency compensation in solid state device (e.g., diode) designs and methods of using the same are described. In some embodiments, the antenna comprises: an antenna aperture having a plurality of RF radiating antenna elements that each include an iris and a solid state device coupled across the iris, wherein the plurality of antenna elements are located in rings with orientation of each of the irises of the antenna elements in at least a portion of each ring rotated with respect to adjacent irises in the portion of each ring while orientation of corresponding solid state devices is uniform; and a controller coupled to control the array of RF radiating antenna elements to tune RF radiating antenna elements to generate one or more beams using the plurality of RF radiating antenna elements.
The described embodiments and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that may be made to the described embodiments by one skilled in the art without departing from the spirit and scope of the described embodiments.
In the following description, numerous details are set forth to provide a more thorough explanation of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.
Techniques disclosed herein allow diodes (e.g., varactor diodes, Schottky diodes, pin diodes, etc.) used as part of antenna elements (e.g., RF radiating unit cells) in an antenna aperture to have a uniform orientation (e.g., a horizontal orientation, a vertical orientation, etc.) while the antenna elements gradually change their orientation. This creates a mis-alignment between diode rotation and cell rotation. Allowing antenna elements to have a uniform orientation is particular useful during manufacturing when using traditional pick and place for diode placement which typically require that the diode orientation not change or only changes in discrete steps (e.g., 90 degrees).
Maintaining uniform orientation of diodes when antenna elements are placed with changes in rotation can cause a frequency shift for every antenna element (e.g., unit cell) because every antenna element will have a slight change in rotation when compared to the other antenna elements adjacent in the row (e.g., rings). Techniques are disclosed herein to allow the resonance frequency of individual antenna elements to be tuned to compensate for frequency shifts.
The following disclosure discusses examples of antenna embodiments, followed by embodiments of diode placement with uniform orientation with respect to rotated antenna elements (e.g., irises), and frequency compensation methods associated with individual antenna elements. Note that while the techniques disclosed herein are described terms of diodes, the techniques are applicable to other solid state devices and/or tuning elements used in antenna elements, such as, for example, but not limited to, transistors (e.g., MOSFETS, BJTs, MOS-capacitors, etc.).
Examples of Antenna Embodiments
Techniques described herein may be used with flat panel satellite antennas. Embodiments of such flat panel antennas are disclosed. The flat panel antennas include one or more arrays of antenna elements on an antenna aperture. In one embodiment, the antenna aperture is a metasurface antenna aperture, such as, for example, the antenna apertures described below. In one embodiment, the antenna elements comprise varactor diode-based antenna elements with diodes and varactors such as described above and described in U.S. Patent Application Publication No. 20210050671, entitled “Metasurface Antennas Manufactured with Mass Transfer Technologies,” published Feb. 18, 2021. In one embodiment, the flat panel antenna is a cylindrically fed antenna that includes matrix drive circuitry to uniquely address and drive each of the antenna elements that are not placed in rows and columns. In one embodiment, the elements are placed in rings.
In one embodiment, the antenna aperture having the one or more arrays of antenna elements is comprised of multiple segments coupled together. When coupled together, the combination of the segments form closed concentric rings of antenna elements. In one embodiment, the concentric rings are concentric with respect to the antenna feed.
In one embodiment, the antenna includes a coaxial feed that is used to provide a cylindrical wave feed via input feed 102. In one embodiment, the cylindrical wave feed architecture feeds the antenna from a central point with an excitation that spreads outward in a cylindrical manner from the feed point. That is, a cylindrically fed antenna creates an outward travelling concentric feed wave. Even so, the shape of the cylindrical feed antenna around the cylindrical feed can be circular, square or any shape. In another embodiment, a cylindrically fed antenna creates an inward travelling feed wave. In such a case, the feed wave most naturally comes from a circular structure.
In one embodiment, antenna elements 103 comprise irises (iris openings) and the aperture antenna of
In one embodiment, each scattering element in the antenna system is part of a unit cell as described above. In one embodiment, the unit cell is driven by the matrix drive embodiments described above. In one embodiment, the diode/varactor in each unit cell has a lower conductor associated with an iris slot separated from an upper conductor associated with its tuning electrode (e.g., iris metal). The diode/varactor can be controlled to adjust the bias voltage between the iris opening and the patch electrode. Using this property, in one embodiment, the diode/varactor integrates an on/off switch for the transmission of energy from the guided wave to the unit cell. When switched on, the unit emits an electromagnetic wave like an electrically small dipole antenna. Note that the teachings herein are not limited to having unit cell that operates in a binary fashion with respect to energy transmission.
In one embodiment, the feed geometry of this antenna system allows the antenna elements to be positioned at forty-five-degree (45°) angles to the vector of the wave in the wave feed. Note that other positions may be used (e.g., at 40° angles). This position of the elements enables control of the free space wave received by or transmitted/radiated from the elements. In one embodiment, the antenna elements are arranged with an inter-element spacing that is less than a free-space wavelength of the operating frequency of the antenna. For example, if there are four scattering elements per wavelength, the elements in the 30 GHz transmit antenna will be approximately 2.5 mm (i.e., ¼ th the 10 mm free-space wavelength of 30 GHz).
In one embodiment, the two sets of elements are perpendicular to each other and simultaneously have equal amplitude excitation if controlled to the same tuning state. Rotating them +/−45 degrees relative to the feed wave excitation achieves both desired features at once. Rotating one set 0 degrees and the other 90 degrees would achieve the perpendicular goal, but not the equal amplitude excitation goal. Note that 0 and 90 degrees may be used to achieve isolation when feeding the array of antenna elements in a single structure from two sides.
The amount of radiated power from each unit cell is controlled by applying a voltage to the varactor diode using a controller. Traces to each varactor diode are used to provide the voltage to the varactor diode. The voltage is used to tune or detune the capacitance and thus the resonance frequency of individual elements to effectuate beam forming. The voltage required is dependent on the diode/varactor being used.
Diode Placement and Orientation
In some embodiments, the antenna aperture has RF radiating antenna elements that each include an iris and a varactor diode coupled across the iris, and the antenna elements are located in rings (or rows). The orientation of each iris of the antenna elements in each ring, or portion thereof, is rotated with respect to the adjacent irises in that ring while orientation of corresponding varactor diodes is uniform.
In some embodiments, the diodes in the antenna aperture have the following characteristics:
Referring to
Slot 201B includes diode 202B coupled in series with capacitor 203B across slot 201B. Slot 201C includes diode 202C coupled in series with capacitor 203C across slot 201C. Slot 201D includes diode 202D coupled in series in with capacitor 203D across slot 201D, and slot 201E includes diode 202E coupled in series with capacitor 203E across slot 201E. As shown in
Referring to
Referring to
Diode 302 is coupled in series with capacitor 304 to create a series connection across slot 305 in the antenna element via bonding pads 303. As shown, bonding pads 303 are circular. However, in other embodiments, diode 302 can have bonding pads that are other shapes, such as, for example, rectangular, square, etc. One of bonding pads 303 is coupled to capacitor 304 via landing pad 306, while another landing pad (not shown) is below and coupled to the other bonding pad 303 of diode 302.
Referring to
Diode 312 is coupled in series with capacitor 314 to create a series connection across slot 315 in the antenna element via bonding pads 313. As shown, bonding pad 313 are circular. However, in other embodiments, diode 312 can have bonding pads that are other shapes, such as, for example, rectangular, square, etc. One of bonding pads 313 is coupled to capacitor 314 via landing pad 316, while another landing pad (not shown) is below and coupled to the other bonding pad 313 of diode 312.
Slot 411 includes diode 412 in a horizontal orientation. Diode 412 is coupled in series with capacitor 413 across slot 411 via bonding pads 414. More specifically, diode 412 is coupled to one slot via its bonding pad 414 and to capacitor 413 via bonding pad 414. Each of bonding pads 414 is coupled to one of landing pads 415
Slot 421 includes diode 422 in a horizontal orientation. Diode 422 is coupled in series with capacitor 423 to create a series connection across slot 421 via bonding pads 424. More specifically, diode 422 is coupled to one slot via its bonding pad 424 and to capacitor 423 via bonding pad 424. Each of bonding pads 424 is coupled to a landing pad (not shown).
Slot 431 includes diode 432 in a horizontal orientation. Diode 432 is coupled in series with capacitor 433 to create a series connection across slot 431 via bonding pads 434. More specifically, diode 432 is coupled to one slot via its bonding pad 434 and to capacitor 433 via bonding pad 434. Each of bonding pads 434 is coupled to a landing pad, such as landing pad 435 (the other landing pad is not shown).
Slot 460 includes diode 465 coupled in series with capacitor 463 to create a series connection across slot 460. Diode 465 is coupled to one side of slot 460 via a bonding pad 461 that is coupled to landing pad 462 which is coupled to the side of slot 460. The other end of diode 465 is coupled via bonding pad 461 and landing pad 462 to capacitor 463. Capacitor 463 is coupled to the other side of slot 460. Note that the bonding pads and landing pads are both rectangular in shape in
Slot 470 includes diode 475 coupled in series with capacitor 473 to create a series of connections across slot 470. Diode 475 is coupled to one side of slot 470 via a bonding pad 471 that is coupled to a landing pad 472, which is coupled to the side of slot 470. The other end of diode 475 is coupled via bonding pad 471 and landing pad 472 to capacitor 473. Capacitor 473 is coupled to the other side of slot 470. Note that the bonding pads and landing pads are both rectangular in shape in
Slot 480 includes diode 485 coupled in series with capacitor 483 to create a series of connections across slot 480. Diode 485 is coupled to one side of slot 480 via a bonding pad 481 that is coupled to a landing pad 482, which is coupled to the side of slot 480. The other end of diode 485 is coupled via bonding pad 481 and landing pad 482 to capacitor 483. Capacitor 483 is coupled to the other side of slot 480. Note that the bonding pads and landing pads are both rectangular in shape in
Referring to
Referring to
Referring to
Referring to
Slot 510 of
Referring to
Referring to
Referring to
Slot 610 of
In some embodiments, as discussed above, the diodes of
Frequency Compensation
In some embodiments, a variety of features can be incorporated in a slot to adjust its perimeter length. Such features can be included on one or both sides or top and/or bottom of a slot. In some embodiments, every slot can have an individually customized feature or size. In some other embodiments, slots can also be binned into sub-groups (e.g., segments, sub-segments, etc.) to lower the variation when the antenna aperture is being manufactured.
In some embodiments, the slot dimensions can be changed directly without adding new features. For example, individual slots can be lengthened or shortened to change the resonance frequency. That is, longer or shorter slots may be used with different perimeter lengths in order to control the resonance frequencies of the antenna elements.
In some embodiments, each diode can have two or more connection pads, which impacts iris loading and thereby affects resonance frequency. In some embodiments, antenna elements can be loaded with different external features such as, for example, dipoles or patches, to tune the resonance of each unit cell depending on its rotation.
In some embodiments, a diode can have two or more connection pads as shown in
Thus, a frequency shift can be made for every unit cell to compensate for the slight change in orientation every cell has with respect to an adjacent cells in the row (e.g., ring). by performing modifications in the size of a slot.
In some embodiments, the tuning of the resonance frequency of individual antenna is made under software control. This may be done in cooperation with the hardware features added to adjust the resonance frequency of individual slots or in lieu of those hardware features. Examples of such software control to cause a frequency adjustment of every cell include controlling the varactor diode to account for the offset frequency. In some embodiments, controlling the varactor diode to account for the offset frequency can be performed by mapping the offset frequency to a voltage offset or modifying the DAC value to incorporate the required voltage offset and applying that offset or the new DAC to the RF element to align the resonance frequencies of all elements. In some embodiments, the DAC values are values supported by an FPGA pattern driver that produces the desired voltage output to the RF elements.
In some embodiments, controlling the varactor diode to account for the offset frequency comprises calculating the resonator model of every slot separately and having each of these models take the actual resonances of that particular unit slot into account. Once the amount of frequency shift for each orientation of an iris is known, the voltage for the diode may be modified in order to compensate for the frequency shift.
Note that adjusting the resonance frequencies of antenna elements may be performed with design and/or manufacturing an antenna aperture, or portion thereof (e.g., an antenna aperture segment, etc.). In some embodiments, the diodes of
Referring to
After determining the rotations, processing logic modifies one or more slots/irises of RF radiating antenna elements to shift its resonance frequency in comparison to other antenna elements of the plurality of RF radiating antenna elements (802). In some embodiments, modifying one or more slots of the RF radiating antenna elements comprises modifying perimeter length of the irises of the one or more antenna elements different than perimeter length of the irises of the other antenna elements. In some embodiments, modifying one or more slots of the RF radiating antenna elements comprises compensating for changes in orientation of irises with respect to adjacently positioned irises in a same ring.
After modifying the slots/irises of the aperture design, processing logic creates the plurality of antenna elements on a surface of a substrate (e.g., a metasurface) of an antenna aperture (803). Such manufacturing techniques are well-known in the art.
In some embodiments, the diodes of
Examples of Antenna Details
The techniques described above may be used with flat panel satellite antennas. Embodiments of such flat panel antennas are disclosed. The flat panel antennas include one or more arrays of antenna elements on an antenna aperture. These antennas include a control structure to control the operations of the antenna including the antenna elements in the antenna aperture.
In one embodiment, the control structure for the antenna system has two main components: the antenna array controller, which includes drive electronics for the antenna system, is below the wave scattering structure of surface scattering antenna elements such as described herein, while the matrix drive switching array is interspersed throughout the radiating RF array in such a way as to not interfere with the radiation. In one embodiment, the drive electronics for the antenna system comprise commercial off-the shelf LCD controls used in commercial television appliances that adjust the bias voltage for each scattering element by adjusting the amplitude or duty cycle of an AC bias signal to that element.
In one embodiment, the antenna array controller also contains a microprocessor executing the software. The control structure may also incorporate sensors (e.g., a GPS receiver, a three-axis compass, a 3-axis accelerometer, 3-axis gyro, 3-axis magnetometer, etc.) to provide location and orientation information to the processor. The location and orientation information may be provided to the processor by other systems in the earth station and/or may not be part of the antenna system.
More specifically, the antenna array controller controls which elements are turned off and those elements turned on and at which phase and amplitude level at the frequency of operation. The elements are selectively detuned for frequency operation by voltage application. In one embodiment, a matrix drive is used to apply voltage to the varactor diode in order to drive each cell separately from all the other cells without having a separate connection for each cell (direct drive). Because of the high density of elements, the matrix drive is an efficient way to address each cell individually.
For transmission, a controller supplies an array of voltage signals to the RF diodes to create a modulation, or control pattern. The control pattern causes the elements to be turned to different states. In one embodiment, multistate control is used in which various elements are turned on and off to varying levels, further approximating a sinusoidal control pattern, as opposed to a square wave (i.e., a sinusoid gray shade modulation pattern). In one embodiment, some elements radiate more strongly than others, rather than some elements radiate and some do not. Variable radiation is achieved by applying specific voltage levels, which adjusts the liquid crystal permittivity to varying amounts, thereby detuning elements variably and causing some elements to radiate more than others.
The generation of a focused beam by the metamaterial array of elements can be explained by the phenomenon of constructive and destructive interference. Individual electromagnetic waves sum up (constructive interference) if they have the same phase when they meet in free space, and waves cancel each other (destructive interference) if they are in opposite phase when they meet in free space. If the slots in a slotted antenna are positioned so that each successive slot is positioned at a different distance from the excitation point of the guided wave, the scattered wave from that element will have a different phase than the scattered wave of the previous slot. If the slots are spaced one quarter of a guided wavelength apart, each slot will scatter a wave with a one fourth phase delay from the previous slot.
Using the array, the number of patterns of constructive and destructive interference that can be produced can be increased so that beams can be pointed theoretically in any direction plus or minus ninety degrees (90°) from the bore sight of the antenna array, using the principles of holography. Thus, by controlling which metamaterial unit cells are turned on or off (i.e., by changing the pattern of which cells are turned on and which cells are turned off), a different pattern of constructive and destructive interference can be produced, and the antenna can change the direction of the main beam. The time required to turn the unit cells on and off dictates the speed at which the beam can be switched from one location to another location.
In one embodiment, the antenna system produces one steerable beam for the uplink antenna and one steerable beam for the downlink antenna. In one embodiment, the antenna system uses metamaterial technology to receive beams and to decode signals from the satellite and to form transmit beams that are directed toward the satellite. In one embodiment, the antenna systems are analog systems, in contrast to antenna systems that employ digital signal processing to electrically form and steer beams (such as phased array antennas). In one embodiment, the antenna system is considered a “surface” antenna that is planar and relatively low profile, especially when compared to conventional satellite dish receivers.
Control module 980, or a controller, is coupled to reconfigurable resonator layer 930 to modulate the array 912 of tunable slots 910 by varying the voltage to the diodes/varactors. Control module 980 may include a Field Programmable Gate Array (“FPGA”), a microprocessor, a controller, System-on-a-Chip (SoC), or other processing logic. In one embodiment, control module 980 includes logic circuitry (e.g., multiplexer) to drive the array 912 of tunable slots 910. In one embodiment, control module 980 receives data that includes specifications for a holographic diffraction pattern to be driven onto the array 912 of tunable slots 910. The holographic diffraction patterns may be generated in response to a spatial relationship between the antenna and a satellite so that the holographic diffraction pattern steers the downlink beams (and uplink beam if the antenna system performs transmit) in the appropriate direction for communication. Although not drawn in each figure, a control module similar to control module 980 may drive each array of tunable slots described in various embodiments in the disclosure.
Radio Frequency (“RF”) holography is also possible using analogous techniques where a desired RF beam can be generated when an RF reference beam encounters an RF holographic diffraction pattern. In the case of satellite communications, the reference beam is in the form of a feed wave, such as feed wave 905 (approximately 20 GHz in some embodiments). To transform a feed wave into a radiated beam (either for transmitting or receiving purposes), an interference pattern is calculated between the desired RF beam (the object beam) and the feed wave (the reference beam). The interference pattern is driven onto the array of tunable slots 910 as a diffraction pattern so that the feed wave is “steered” into the desired RF beam (having the desired shape and direction). In other words, the feed wave encountering the holographic diffraction pattern “reconstructs” the object beam, which is formed according to design requirements of the communication system. The holographic diffraction pattern contains the excitation of each element and is calculated by whologram=w*inwout, with win as the wave equation in the waveguide and wout the wave equation on the outgoing wave.
A voltage between the varactor diode and the iris opening can be modulated to tune the antenna element (e.g., the tunable resonator/slot). Adjusting the voltage varies the capacitance of a slot (e.g., the tunable resonator/slot). Accordingly, the reactance of a slot (e.g., the tunable resonator/slot) can be varied by changing the capacitance. Resonant frequency of the slot also changes according to the equation
where f is the resonant frequency of the slot and L and C are the inductance and capacitance of the slot, respectively. The resonant frequency of the slot affects the energy radiated from feed wave 905 propagating through the waveguide. As an example, if feed wave 905 is 20 GHz, the resonant frequency of a slot 910 may be adjusted (by varying the capacitance) to 17 GHz so that the slot 910 couples substantially no energy from feed wave 905. Or, the resonant frequency of a slot 910 may be adjusted to 20 GHz so that the slot 910 couples energy from feed wave 905 and radiates that energy into free space. Although the examples given are binary (fully radiating or not radiating at all), full gray scale control of the reactance, and therefore the resonant frequency of slot 910 is possible with voltage variance over a multi-valued range. Hence, the energy radiated from each slot 910 can be finely controlled so that detailed holographic diffraction patterns can be formed by the array of tunable slots.
In one embodiment, tunable slots in a row are spaced from each other by λ/5. Other spacings may be used. In one embodiment, each tunable slot in a row is spaced from the closest tunable slot in an adjacent row by λ/2, and, thus, commonly oriented tunable slots in different rows are spaced by λ/4, though other spacings are possible (e.g., λ/5, λ/6.3). In another embodiment, each tunable slot in a row is spaced from the closest tunable slot in an adjacent row by λ/3.
Referring to
Separate from conducting ground plane 902 is interstitial conductor 903, which is an internal conductor. In one embodiment, conducting ground plane 902 and interstitial conductor 903 are parallel to each other. In one embodiment, the distance between ground plane 902 and interstitial conductor 903 is 0.1-0.15″. In another embodiment, this distance may be λ/2, where λ, is the wavelength of the travelling wave at the frequency of operation.
Ground plane 902 is separated from interstitial conductor 903 via a spacer 904. In one embodiment, spacer 904 is a foam or air-like spacer. In one embodiment, spacer 904 comprises a plastic spacer.
On top of interstitial conductor 903 is dielectric layer 905. In one embodiment, dielectric layer 905 is plastic. The purpose of dielectric layer 905 is to slow the travelling wave relative to free space velocity. In one embodiment, dielectric layer 905 slows the travelling wave by 30% relative to free space. In one embodiment, the range of indices of refraction that are suitable for beam forming are 1.2-1.8, where free space has by definition an index of refraction equal to 1. Other dielectric spacer materials, such as, for example, plastic, may be used to achieve this effect. Note that materials other than plastic may be used as long as they achieve the desired wave slowing effect. Alternatively, a material with distributed structures may be used as dielectric layer 905, such as periodic sub-wavelength metallic structures that can be machined or lithographically defined, for example.
An RF array 906 is on top of dielectric layer 905. In one embodiment, the distance between interstitial conductor 903 and RF array 906 is 0.1-0.15″. In another embodiment, this distance may be λeff/2, where λeff is the effective wavelength in the medium at the design frequency.
The antenna includes sides 907 and 908. Sides 907 and 908 are angled to cause a travelling wave feed from coax pin 901 to be propagated from the area below interstitial conductor 903 (the spacer layer) to the area above interstitial conductor 903 (the dielectric layer) via reflection. In one embodiment, the angle of sides 907 and 908 are at 45° angles. In an alternative embodiment, sides 907 and 908 could be replaced with a continuous radius to achieve the reflection. While
In operation, when a feed wave is fed in from coaxial pin 901, the wave travels outward concentrically oriented from coaxial pin 901 in the area between ground plane 902 and interstitial conductor 903. The concentrically outgoing waves are reflected by sides 907 and 908 and travel inwardly in the area between interstitial conductor 903 and RF array 906. The reflection from the edge of the circular perimeter causes the wave to remain in phase (i.e., it is an in-phase reflection). The travelling wave is slowed by dielectric layer 905. At this point, the travelling wave starts interacting and exciting with elements in RF array 906 to obtain the desired scattering.
To terminate the travelling wave, a termination 909 is included in the antenna at the geometric center of the antenna. In one embodiment, termination 909 comprises a pin termination (e.g., a 50Ω pin). In another embodiment, termination 909 comprises an RF absorber that terminates unused energy to prevent reflections of that unused energy back through the feed structure of the antenna. These could be used at the top of RF array 906.
In operation, a feed wave is fed through coaxial pin 1015 and travels concentrically outward and interacts with the elements of RF array 1016.
The cylindrical feed in both the antennas of
Embodiments of the antenna having a cylindrical feed solve one or more problems. These include dramatically simplifying the feed structure compared to antennas fed with a corporate divider network and therefore reducing total required antenna and antenna feed volume; decreasing sensitivity to manufacturing and control errors by maintaining high beam performance with coarser controls (extending all the way to simple binary control); giving a more advantageous side lobe pattern compared to rectilinear feeds because the cylindrically oriented feed waves result in spatially diverse side lobes in the far field; and allowing polarization to be dynamic, including allowing left-hand circular, right-hand circular, and linear polarizations, while not requiring a polarizer.
Array of Wave Scattering Elements
RF array 906 of
In one embodiment, the cylindrical feed geometry of this antenna system allows the unit cells elements to be positioned at forty-five-degree (45°) angles to the vector of the wave in the wave feed. This position of the elements enables control of the polarization of the free space wave generated from or received by the elements. In one embodiment, the unit cells are arranged with an inter-element spacing that is less than a free-space wavelength of the operating frequency of the antenna. For example, if there are four scattering elements per wavelength, the elements in the 30 GHz transmit antenna will be approximately 2.5 mm (i.e., ¼ th the 10 mm free-space wavelength of 30 GHz).
Cell Placement
In one embodiment, the antenna elements are placed on the cylindrical feed antenna aperture in a way that allows for a systematic matrix drive circuit. The placement of the cells includes placement of the transistors for the matrix drive.
In an initial approach to realize matrix drive circuitry on the cylindrical feed antenna with unit cells placed in a non-regular grid, two steps are performed. In the first step, the cells are placed on concentric rings and each of the cells is connected to a transistor that is placed beside the cell and acts as a switch to drive each cell separately. In the second step, the matrix drive circuitry is built in order to connect every transistor with a unique address as the matrix drive approach requires. Because the matrix drive circuit is built by row and column traces (similar to LCDs) but the cells are placed on rings, there is no systematic way to assign a unique address to each transistor. This mapping problem results in very complex circuitry to cover all the transistors and leads to a significant increase in the number of physical traces to accomplish the routing. Because of the high density of cells, those traces disturb the RF performance of the antenna due to coupling effect. Also, due to the complexity of traces and high packing density, the routing of the traces cannot be accomplished by commercially available layout tools.
In one embodiment, the matrix drive circuitry is predefined before the cells and transistors are placed. This ensures a minimum number of traces that are necessary to drive all the cells, each with a unique address. This strategy reduces the complexity of the drive circuitry and simplifies the routing, which subsequently improves the RF performance of the antenna.
More specifically, in one approach, in the first step, the cells are placed on a regular rectangular grid composed of rows and columns that describe the unique address of each cell. In the second step, the cells are grouped and transformed to concentric circles while maintaining their address and connection to the rows and columns as defined in the first step. A goal of this transformation is not only to put the cells on rings but also to keep the distance between cells and the distance between rings constant over the entire aperture. In order to accomplish this goal, there are several ways to group the cells.
In one embodiment, a TFT package is used to enable placement and unique addressing in the matrix drive.
An Example of a Full Duplex Communication System
In another embodiment, the combined antenna apertures are used in a full duplex communication system.
Referring to
Diplexer 1345 is coupled to a low noise block down converter (LNBs) 1327, which performs a noise filtering function and a down conversion and amplification function in a manner well-known in the art. In one embodiment, LNB 1327 is in an out-door unit (ODU). In another embodiment, LNB 1327 is integrated into the antenna apparatus. LNB 1327 is coupled to a modem 1360, which is coupled to computing system 1340 (e.g., a computer system, modem, etc.).
Modem 1360 includes an analog-to-digital converter (ADC) 1322, which is coupled to LNB 1327, to convert the received signal output from diplexer 1345 into digital format. Once converted to digital format, the signal is demodulated by demodulator 1323 and decoded by decoder 1324 to obtain the encoded data on the received wave. The decoded data is then sent to controller 1325, which sends it to computing system 1340.
Modem 1360 also includes an encoder 1330 that encodes data to be transmitted from computing system 1340. The encoded data is modulated by modulator 1331 and then converted to analog by digital-to-analog converter (DAC) 1332. The analog signal is then filtered by a BUC (up-convert and high pass amplifier) 1333 and provided to one port of diplexer 1345. In one embodiment, BUC 1333 is in an out-door unit (ODU).
Diplexer 1345 operating in a manner well-known in the art provides the transmit signal to antenna 1301 for transmission.
Controller 1350 controls antenna 1301, including the two arrays of antenna elements on the single combined physical aperture.
The communication system would be modified to include the combiner/arbiter described above. In such a case, the combiner/arbiter after the modem but before the BUC and LNB.
Note that the full duplex communication system shown in
With reference to
There is a number of example embodiments described herein.
Example 1 is an antenna comprising: an antenna aperture having a plurality of RF radiating antenna elements that each include an iris and a solid state device coupled across the iris, wherein the plurality of antenna elements are located in rings with orientation of each of the irises of the antenna elements in at least a portion of each ring rotated with respect to adjacent irises in the portion of said each ring while orientation of corresponding solid state devices is uniform; and a controller coupled to control the array of RF radiating antenna elements to tune RF radiating antenna elements to generate one or more beams using the plurality of RF radiating antenna elements.
Example 2 is the antenna of example 1 that may optionally include that one or more antenna elements of the plurality of RF radiating antenna elements includes a modification in size from other antenna elements of the plurality of antenna elements to shift its resonance frequency in comparison to the other antenna elements.
Example 3 is the antenna of example 2 that may optionally include that the modification makes perimeter length of the irises of the one or more antenna elements different than perimeter length of the irises of the other antenna elements.
Example 4 is the antenna of example 2 that may optionally include that the modification compensates for changes in orientation of irises with respect to adjacently positioned irises in a same ring.
Example 5 is the antenna of example 2 that may optionally include that modification includes one or more notches on one or more sides of at least one iris of the one or more antenna elements.
Example 6 is the antenna of example 2 that may optionally include that modification includes one or more notches on one or more of a top and bottom at least one iris of the one or more antenna elements.
Example 7 is the antenna of example 2 that may optionally include that modification includes one or more bars extending, from one or more sides, into an interior of at least one iris of the one or more antenna elements.
Example 8 is the antenna of example 2 that may optionally include that modification includes longer sides of at least one iris of the one or more antenna elements.
Example 9 is the antenna of example 2 that may optionally include that modification includes position, shape or size of one or more landing pads of at least one iris of the one or more antenna elements.
Example 10 is the antenna of example 1 that may optionally include that one or more antenna elements of the plurality of RF radiating antenna elements includes a resonance frequency adjusted via software to shift its resonance frequency in comparison to the other antenna elements.
Example 11 is the antenna of example 1 that may optionally include that each antenna element of the plurality of antenna elements further comprises a capacitor coupled in series with the solid state device of said each antenna element and that the solid state device comprises a diode.
Example 12 is the antenna of example 1 that may optionally include that each antenna element of the plurality of antenna elements further comprises two or more landing pads coupling its solid state device to its corresponding iris.
Example 13 is the antenna of example 12 that may optionally include that the landing pads are rectangular or circular in shape.
Example 14 is the antenna of example 12 that may optionally include that the landing pads comprises three landing pads, wherein two of the three landing pads are RF landing pads and one of the three landing pads is a direct current (DC) landing pad for transferring a voltage to the solid state device of said each antenna element.
Example 15 is an antenna comprising: an antenna aperture having a plurality of RF radiating antenna elements that each include an iris and a solid state device coupled across the iris, wherein the plurality of antenna elements are located in rings with orientation of each of the irises of the antenna elements in at least a portion of each ring rotated with respect to adjacent irises in the portion of said each ring while orientation of corresponding solid state devices is uniform. One or more antenna elements of the plurality of RF radiating antenna elements includes a modification in size from other antenna elements of the plurality of antenna elements to shift its resonance frequency in comparison to the other antenna elements, and each antenna element of the plurality of antenna elements further comprises three landing pads coupling its solid state device to its corresponding iris, wherein two of the three landing pads are RF landing pads and one of the three landing pads is a direct current (DC) landing pad for transferring a voltage to the solid state device of said each antenna element. The antenna also includes a controller coupled to control the array of RF radiating antenna elements to tune RF radiating antenna elements to generate one or more beams using the plurality of RF radiating antenna elements.
Example 16 is the antenna of example 15 that may optionally include that the modification makes perimeter length of the irises of the one or more antenna elements different than perimeter length of the irises of the other antenna elements.
Example 17 is the antenna of example 15 that may optionally include that the modification compensates for changes in orientation of irises with respect to adjacently positioned irises in a same ring.
Example 18 is the antenna of example 1 that the solid state device comprises a diode.
Example 19 is a method comprising: determining rotations with respect to irises of a plurality of RF radiating antenna elements of an antenna aperture, each of the plurality of RF radiating antenna elements including a solid state device coupled across the iris; modifying one or more irises of one or more of the plurality of RF radiating antenna elements to shift its resonance frequency in comparison to other antenna elements of the plurality of RF radiating antenna elements; and creating the plurality of antenna elements on a surface of a substrate of an antenna aperture.
Example 20 is the method of example 19 that may optionally include that modifying one or more irises of one or more of the plurality of RF radiating antenna elements comprises modifying perimeter length of the irises of the one or more antenna elements different than perimeter length of the irises of the other antenna elements.
Example 21 is the method of example 19 that may optionally include that modifying one or more irises of one or more of the plurality of RF radiating antenna elements comprises compensating for changes in orientation of irises with respect to adjacently positioned irises in a same ring.
Example 22 is the method of example 19 that may optionally include that the solid state device comprises a diode.
All of the methods and tasks described herein may be performed and fully automated by a computer system. The computer system may, in some cases, include multiple distinct computers or computing devices (e.g., physical servers, workstations, storage arrays, cloud computing resources, etc.) that communicate and interoperate over a network to perform the described functions. Each such computing device typically includes a processor (or multiple processors) that executes program instructions or modules stored in a memory or other non-transitory computer-readable storage medium or device (e.g., solid state storage devices, disk drives, etc.). The various functions disclosed herein may be embodied in such program instructions, or may be implemented in application-specific circuitry (e.g., ASICs or FPGAs) of the computer system. Where the computer system includes multiple computing devices, these devices may, but need not, be co-located. The results of the disclosed methods and tasks may be persistently stored by transforming physical storage devices, such as solid-state memory chips or magnetic disks, into a different state. In some embodiments, the computer system may be a cloud-based computing system whose processing resources are shared by multiple distinct business entities or other users.
Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described operations or events are necessary for the practice of the algorithm). Moreover, in certain embodiments, operations or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially.
The various illustrative logical blocks, modules, routines, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware (e.g., ASICs or FPGA devices), computer software that runs on computer hardware, or combinations of both. Moreover, the various illustrative logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a processor device, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor device can be a microprocessor, but in the alternative, the processor device can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor device can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor device includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. A processor device can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor device may also include primarily analog components. For example, some or all of the rendering techniques described herein may be implemented in analog circuitry or mixed analog and digital circuitry. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.
The elements of a method, process, routine, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor device, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory computer-readable storage medium. An exemplary storage medium can be coupled to the processor device such that the processor device can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor device. The processor device and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor device and the storage medium can reside as discrete components in a user terminal.
Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements or steps. Thus, such conditional language is not generally intended to imply that features, elements or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without other input or prompting, whether these features, elements or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
Disjunctive language such as the phrase “at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present.
While the above detailed description has shown, described, and pointed out novel features as applied to various embodiments, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the spirit of the disclosure. As can be recognized, certain embodiments described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others. The scope of certain embodiments disclosed herein is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
The present application is a non-provisional application of and claims the benefit of U.S. Provisional Patent Application No. 63/170,994, entitled “Cell Rotations and Frequency Compensation in Varactor Designs,” filed Apr. 5, 2021, which is incorporated by reference in its entirety.
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Number | Date | Country | |
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63170994 | Apr 2021 | US |