The present invention relates generally to a substrate integrated waveguide switch and method of operating the substrate integrated waveguide switch, and, in particular embodiments, to a substrate integrated waveguide switch for RF signals, microwave signals or millimeter wave signals and a method for operating such a switch for these signals.
Substrate Integrated Waveguides (SIWs) are integrated waveguide-like structures fabricated by using two rows of conducting cylinders or slots embedded in a dielectric substrate. These rows of conducting cylinders electrically connect two parallel metal plates. In this way, the non-planar rectangular waveguide can be made in planar form, compatible with existing planar processing techniques.
In accordance with an embodiment of the present invention, a system comprises a dielectric substrate and a multi-throw switch supported by the dielectric substrate, the multi-throw switch comprising at least one first transmission path, at least one first switching element in each of the at least one first transmission path, a second transmission path, and at least one second switching element in the second transmission path, wherein the multi-throw switch is configured to direct propagation of an electromagnetic signal along the at least one first transmission path when the at least one first switching element passes the electromagnetic signal and the at least one second switching element blocks the electromagnetic signal, and wherein the multi-throw switch is configured to direct the propagation of the electromagnetic signal along the second transmission path when the at least one second switching element passes the electromagnetic signal and the at least one first switching element blocks the electromagnetic signal.
In accordance with an embodiment of the present invention, a system comprises a dielectric substrate comprising an upper surface and a lower surface, an upper conductive layer disposed at the upper surface, the upper conductive layer comprising transmission arms, a lower conductive layer disposed at the lower surface, and vertical conductive elements located at edges of the transmission arms of the upper conductive layer, the vertical conductive elements electrically connecting the upper conductive layer with the lower conductive layer. The system further comprises reconfigurable electromagnetic band gap (EBG) structures located at least at some transmission arms, the reconfigurable EBG structures configured to pass or block an electromagnetic signal through the respective transmission arms.
In accordance with an embodiment of the present invention, an arrangement a system comprising a dielectric substrate and a multi-throw switch supported by the dielectric substrate, the multi-throw switch. The multi-throw switch further comprises at least one first transmission path, at least one first switching element in each first transmission path, a second transmission path, and at least one second switching element in each second transmission path, wherein the multi-throw switch is configured to direct propagation of an electromagnetic signal along the at least one first transmission path when the at least one first switching element passes the electromagnetic signal and at least one second switching element blocks the electromagnetic signal, and wherein the multi-throw switch is configured to direct the propagation of the electromagnetic signal along the second transmission path when the at least one second switching element passes the electromagnetic signal and the at least one first switching element blocks the electromagnetic signal.
In accordance with an embodiment of the present invention, a system comprises a dielectric substrate and a single-throw switch supported by the dielectric substrate, wherein the single-throw switch includes a transmission path and at least one switching element in the transmission path, wherein the single-throw switch is configured to direct propagation of an electromagnetic signal along the transmission path when the at least one switching element passes the electromagnetic signal, and wherein the single-throw switch is configured to block the propagation of the electromagnetic signal along the transmission path when the at least one switching element blocks the electromagnetic signal.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
A problem with conventional RF switches is that they are bulky, need extra connectors and cables and have a high insertion loss.
Embodiments of the invention provide a system on substrate switch that switches electromagnetic signals by reconfigurable electromagnetic band gap (EBG) structures to different transmission paths of the switch. Further embodiments disclose that the reconfigurable EBG structures comprise EBGs and tunable elements such as PIN diodes and MEMS devices. The tunable elements may be part of the system on substrate. The tunable elements may apply a load to the EBGs thereby controlling the propagation of the electromagnetic signal.
Substrate integrated waveguide (SIW) structures exhibit propagation characteristics similar to the ones of classical rectangular waveguides, including the field pattern and the dispersion characteristics. Moreover, SIW structures preserve most of the advantages of conventional metallic waveguides, namely high quality-factor and high power-handling capability with self-consistent electrical shielding. The most significant advantage of SIW technology is the possibility to integrate all the components on the same substrate, including passive components, active elements and even antennas. Moreover, there is the possibility to mount one or more chip-sets on the same substrate. There is no need for transitions between elements fabricated with different technologies, thus reducing losses and parasitics. In this way, the concept can be extended to the system-on-substrate including waveguide elements and circuit elements. A system-on substrate represents the ideal platform for developing cost-effective, easy-to-fabricate and high performance microwave systems.
The SIW switch 10 may be incorporated in a dielectric substrate 20. The dielectric substrate 20 may comprise a circuit board such as a printed circuit board or a low-temperature co-fired ceramic (LTCC).
The substrate 20 is generally a thin film substrate having a thickness thinner than, in most cases, around 600 μm, or thinner than around 500 μm, although thicker substrate structures are technically possible. The thin film substrate comprises an electrically insulating material, e.g., a dielectric material, with or without conductive layers. The substrate may comprise a laminate. The thin film substrate does not include a semiconductor material in some embodiments. Typical thin film substrate materials may be flexible printed circuit board materials such as polyimide foils, polyethylene naphthalate (PEN) foils, polyethylene foils, polyethylene terephthalate (PET) foils, and liquid crystal polymer (LCP) foils. Further substrate materials include polytetrafluoroethylene (PTFE) and other fluorinated polymers, such as perfluoroalkoxy (PFA) and fluorinated ethylene propylene (FEP), Cytop® (amorphous fluorocarbon polymer), and HyRelex materials available from Taconic. In some embodiments the substrate 20 is a multi-dielectric layer substrate.
The switch 10 comprises a first conductive layer or line 15 (e.g., a top metal layer) and a second conductive layer or line 16 (e.g., bottom metal layer). The top conductive layer 15 may comprise the form of a T. The bottom layer 16 may mirror the top layer's T or may be a substantially larger T. Alternatively, the bottom layer 16 may be a plate such as plate covering the entire bottom surface of the substrate 20, or a plate that covers the T of the first conductive layer 15 and at least a majority of the bottom surface of the substrate 20. The top and the bottom conductive layers 15, 16 are parallel to each other and may be disposed on the upper surface and the lower surface of the substrate 20. In alternative embodiments these layers 15, 16 are embedded in the substrate 20.
The top layer 15 and the bottom layer 16 are connected by rows of conductive vertical elements such as conductive cylinders, slots or vias 17, 18, 19. The rows of vertical conductive elements 17, 18, 19 are arranged substantially vertical to the top layer 15 and the bottom layer 16 along the edges of the T. The rows of the vertical elements 17, 18, 19 are substantially parallel to each other in most embodiments. The distance between the rows of conductive vertical elements 17, 18, 19 dependents on the operation frequency of the electromagnetic signal. The materials of the top conductive layer 15, the bottom conductive layer 16, and the rows of vertical conductive elements 17, 18, 19 may be copper, aluminum, alloys of copper or aluminums, or combination thereof. In alternative embodiments other conductive material may be used.
The length of the SIW switch 10 can be selected and adapted based on the particular application. Non-limiting examples of suitable switch lengths can be a few hundred micrometers to tens of millimeters. The height of the conductive vertical elements 17, 18, 19 may correspond to the thickness of the substrate 20.
The SIW switch 10 further comprises switching elements such as reconfigurable electromagnetic band gap (EBG) structures 31-36. The switching elements 31-36 are configured to open or block a transmission path for an electromagnetic signal. For example, the switching elements 34-36 can block or pass RF signals (e.g., an RF frequency band) from the input port 11 (through a first transmission arm 150) to the first output port 12 (through a second transmission arm 151) along a first transmission path of the switch 10 and the switching elements 31-33 can block or pass RF signals from the input port 11 (through the first transmission arm 150) to the second output port 13 (through the second transmission arm 152) along a second transmission path. As can be seen from
As can be seen from
The switching elements 31-36 are able to reconfigure the load of the switching elements 31-36 in the second and third transmission arms (output arms) 151, 152 of the switch 10. By modifying adequately the load of the switching elements 31-36 through the tunable elements 315 the switch 10 can control the propagation of the electromagnetic signal (e.g., RF signal) from the input port 11 to the output ports 12, 13.
The EBG structure 311 may be a conductive via (e.g., metal via) connecting the conductive connection line 312 to the bottom conductive layer 16. The top conductive layer 15 is electrically isolated from the EBG structure 311 and the conductive connection line 312 by the substrate material of the substrate 20 or by an additional dielectric layer. The EBG structure 311 and the conductive connection line 312 may be from the same material. For example, the material may be copper, aluminum, alloys of copper or aluminum, or combinations thereof. The material of the EBG structure 311 and the conductive connection line 312 may be the same as the top metal layer 15. In alternative embodiments the EBG structure 311 may have a mushroom structure.
The conductive connection line 312 may be connected to a tunable element 315. The tunable element may be a diode (such as a PIN diode), a MEMS device, a transistor device or another tunable device. Alternatively, the tunable element 315 is a discrete device or a simple ASIC. The tunable element 315 may be disposed on the substrate 20 (e.g., the circuit board) as a substrate mount device (SMD). Furthermore, a stub 317 is also connected to the tunable element 315. The stub 317 acts as a ground for the electromagnetic signal (e.g., RF signal). For example, the stub 317 may be a quarter wavelength open stub (or RF-choke).
The tunable elements 315 may be connected to additional conductive (digital) lines disposed within or on the substrate 20. The additional conductive (digital) lines may be (directly or indirectly) connected to an I/O device or I/O terminal for each tunable element 315. The conductive (digital) line is configured to provide a digital signal to the tunable element 315 in order to switch it ON or OFF. The tunable elements may be selected together or may be selected individually. For example, the tunable elements 315 in each throw prong 152, 153 may be selected and switched together. This is shown in
When the tunable elements 315 are switched on a DC power is applied to the EBG structure 311 and a certain load (capacitive or inductive) is placed on the EBG structures 311, and when the tunable elements 315 are switched off a different load is applied to the EBG structures 315.
The EBG structures 311 may be located at the middle line M of each throw prong 151, 152 of the top metal layer 15. The middle line M is the middle of the width w of the RF transmission line. In some embodiments the EBG structures 311 may be located substantially at the middle line 15 or anywhere in the width w. The width w of the SIW switch 10 may be about a half of guided wavelength.
The conductive connection lines 312 may comprise different lengths l1. The length l1 is measured from the contact of the EBG structure 311 to the contact of the tunable element 315. For example, the distance is about a little less than a quarter guided waveguide, e.g., a quarter guided wavelength minus less or equal 5%, or alternatively, minus less or equal 10%. In some embodiments all the lengths l1 of the conductive connection lines 312 are different for all switching elements 31-33 and 34-36 in each throw prong 151, 152. Alternatively, the lengths l1 of the two outer conductive connection lines 312 of the switching elements (31 and 33 on throw prong 152 and 34 and 36 on throw prong 151) are the same while the middle conductive connection lines 312 of the switching elements 32 and 35 are the different (shorter or longer). In some embodiments the lengths l1 of the conductive lines 312 of the switching elements 31-33 mirror the lengths l1 of the conductive lines 312 of the switching elements 34-36.
Moreover, the conductive connection lines 312 are laterally spaced apart from each other by a distance d. All the distances may be different. For example, distance d12 is different than distance d23, and distance d45 is different than distance d56. The distances d are measured from the middle to middle of adjacent conductive connection lines 312. In some embodiments the distances d of the conductive connection lines 312 of the prong 152 and 151 mirror each other. In other words distance d12 is substantially the same as distance d56 and distance d23 is substantially the same as distance d45 in order to keep symmetry between output ports. Substantially the same means within 10% of the measured distance d (e.g., within 10% of the distance d12). In some embodiments the distances d12 and d23 are optimized and can be different to optimize the frequency response of the switch. These distances are about a quarter wavelength of the guided electromagnetic signal. The distance 312 is optimized for each circuit connected to a tunable element to optimize the frequency response of the switch. This distance may be smaller than a quarter guided wavelength. The RF chokes 317 are about a quarter guided wavelength.
Figure if shows the high quality of an SIW switch 10 according to embodiments. The insertion loss for a RF transmission in a wide band (1 GHz band between 5 GHz and 6 GHz) between input port 11 and output port 12 is less than 0.5 dB, a return loss at the input port 11 is less than −18 dB and the isolation between port 11 and port 13 is less than −20 dB. These results are obtained with an accurate analysis that takes into account the exact model of a real PIN diode with 2Ω serial resistance.
In some embodiments the SIW switch 10 may have a metal via 319 connecting the top conductive layer 15 to the bottom conductive layer 16 at the center of the T junction. Such metal via 319 may improve the quality of the SIW switch 10 for RF transmissions even further.
Also, the same discussion applies with respect to the location of the EBG structure 411 at each output arm 451-453, with respect to the lengths l1 of the conductive connection lines 412, with respect to the distances d1 and d2 between the conductive lines 412 and with respect to the arrangement of the switching elements (e.g., 51-53) in a second transmission arm of the switch (e.g., 451) to the arrangement of the switching elements (e.g., 54-56 or 57-59) in other transmission arms of the switch (e.g., 452 or 453).
In some embodiments, however, the SIW switch 40 may not have a metal via being connected between the top conductive layer 15 and the bottom conductive layer 16 at the center of the junction.
In simulations the quality of the SIW switch 40 has been tested.
Also, the same discussion applies with respect to the location of the EBG structure at each output arm element 651-653, with respect to the lengths l1 of the conductive connection lines, with respect to the distances between the conductive lines and with respect to the arrangement of the switching elements (e.g., 71-73) in an output arm (e.g., 651) to the arrangement of the switching elements (e.g., 74-76 or 77-79) in other output arms (e.g., 652 or 653).
In some embodiments, however, the SIW switch 60 may have three metal vias 81-83 being connected between the top conductive layer 15 and the bottom conductive layer 16 at the junction. The metal vias may be symmetrically located around the coaxial feed line (e.g., coaxial cable) 84. The positions of these vias are optimized for a good frequency response of the switch.
In simulations the quality of the SIW switch 60 has been tested.
Further embodiments may comprise double-pole-double throw switches to switch between two inputs ports and two output ports or any other single or multi-pole multi throw switch.
Other embodiments may include a single pole-single throw switch. A system based on a single pole single throw switch may include a dielectric substrate, and a single pole-single-throw switch supported by the dielectric substrate, wherein the single-throw switch includes a transmission path and at least one switching element in the transmission path, wherein the single-throw switch is configured to direct propagation of an electromagnetic signal along the transmission path when the at least one switching element passes the electromagnetic signal and wherein the single-throw switch is configured to block the propagation of the electromagnetic signal along the transmission path when the at least one switching element blocks the electromagnetic signal. The single pole-single throw switch can be combined with all disclosed switching elements embodiments.
Embodiments of the invention may be applied to radar system such as automotive radar or telecommunication applications such as transceiver applications in base stations or user equipment (e.g., hand held devices).
Embodiments of the invention include a system comprising a dielectric substrate and a multi-throw switch supported by the dielectric substrate comprising, wherein the multi-throw switch includes at least one first transmission path, a second transmission path and at least one switching element located in each transmission path, wherein the multi-throw switch is configured to direct propagation of an electromagnetic signal along the at least one first transmission path when at least one first switching element passes the electromagnetic signal and at least one second switching element blocks the electromagnetic signal, and wherein the multi-throw switch is configured to direct the propagation of the electromagnetic signal along the second transmission path when the at least one second switching element passes the electromagnetic signal and the at least one first switching element blocks the electromagnetic signal.
Embodiments of the invention provide that the at least one switching element comprises an EBG structure and a tunable element, wherein the at least one switching element is configured to pass the electromagnetic signal when the tunable element applies a load to the EBG structure, and wherein the switching element is configured to block the electromagnetic signal when the tunable element applies a different load to the EBG structure.
Embodiments of the invention provide that the tunable element is a PIN diode or a MEMS device.
Embodiments of the invention provide that the at least one switching element comprises at least two switching elements, each switching element comprises an EBG structure electrically connected to a tunable element through a conductive connection line, and wherein the conductive connection lines do not have the same length.
Embodiments of the invention further provide that the at least one switching element comprises at least three switching elements, each switching element comprises an EBG structure electrically connected to a tunable element through a conductive connection line, and wherein a distance d1 between a first conductive connection line and a second conductive connection line is different to a distance d2 between the second conductive connection line and a third conductive connection line.
Embodiments of the invention further include a third transmission path, wherein the multi-throw switch is configured to direct propagation of an electromagnetic signal along a third transmission path when at least one third switching element passes the electromagnetic signal and the at least one first and second switching elements block the electromagnetic signal.
Embodiments of the invention provide that the multi-throw switch is a single pole double-throw switch, a single pole triple-throw switch, or a double pole double-throw switch.
Embodiments of the invention further include a coaxial cable connected to the multi-throw switch.
Embodiments of the invention comprise a system including a dielectric substrate comprising an upper surface and a lower surface, an upper conductive layer disposed at the upper surface, the upper conductive layer comprising transmission arms and a lower conductive layer disposed at the lower surface. The system further comprises vertical conductive elements located at edges of the transmission arms of the upper conductive layer, the vertical conductive elements electrically connecting the upper conductive layer with the lower conductive layer, and reconfigurable electromagnetic band gap (EBG) structures located at least at some transmission arms, the reconfigurable EBG structures configured to pass or block an electromagnetic signal through the respective transmission arms.
Embodiments of the invention provide that the reconfigurable EBG structure comprises an EBG structure and a tunable element, wherein the reconfigurable EBG structure is configured to pass the electromagnetic signal when the tunable element does not apply a load to the EBG structure, and wherein the reconfigurable EBG structure is configured to block the electromagnetic signal when the tunable element applies the load to the EBG structure.
Embodiments of the invention provide that the reconfigurable EBG structures located at least at some of the transmission arms comprises the reconfigurable EBG structures located at two output arms and not located at an input arm.
Embodiments of the invention provide that the reconfigurable EBG structures located at least at some of the transmission arms comprises the reconfigurable EBG structures located at three output arms and not located at an input arm.
Embodiments of the invention provide that the reconfigurable EBG structures located at least at some of the transmission arms comprises the reconfigurable EBG structures located at all output arms and further comprising a feed line connected to the lower conductive layer.
Embodiments of the invention provide that the feed line comprises a coaxial cable.
Embodiments of the invention provide that each transmission arm that comprises the reconfigurable EBG structures comprises at least two reconfigurable EBG structures, each reconfigurable EBG structure comprises an EBG structure electrically connected to a tunable element through a conductive connection line, and wherein the conductive connection lines do not have the same length.
Embodiments of the invention provide that each transmission arm that comprises the reconfigurable EBG structures comprises at least three reconfigurable EBG structures, each reconfigurable EBG structure comprises an EBG structure electrically connected to a tunable element through a conductive connection line, and wherein a distance d1 between a first conductive connection line and a second conductive connection line is different to a distance d2 between the second conductive connection line and a third conductive connection line.
Embodiments of the invention provide a method comprising applying the electromagnetic signal to the system, blocking the electromagnetic signal to a first output port by applying a load to reconfigurable EBG structures in a first transmission arm, and passing the electromagnetic signal to a second output port by not applying the load to reconfigurable EBG structures in a second transmission arm.
Embodiments provide an arrangement comprising a system, wherein the system comprises a dielectric substrate and a multi-throw switch supported by the dielectric substrate, wherein the multi-throw switch includes at least one first transmission path, a second transmission path, and at least one switching element located in each transmission path, wherein the multi-throw switch is configured to direct propagation of an electromagnetic signal along the at least one first transmission path when at least one first switching element passes the electromagnetic signal and at least one second switching element blocks the electromagnetic signal, and wherein the multi-throw switch is configured to direct the propagation of the electromagnetic signal along the second transmission path when the at least one second switching element passes the electromagnetic signal and the at least one first switching element blocks the electromagnetic signal.
Embodiments of the invention provide that the system is a base station, a user equipment or a radar.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
Number | Name | Date | Kind |
---|---|---|---|
5116807 | Romanofsky | May 1992 | A |
5268696 | Buck | Dec 1993 | A |
6373349 | Gilbert | Apr 2002 | B2 |
6452465 | Brown | Sep 2002 | B1 |
6864848 | Sievenpiper | Mar 2005 | B2 |
7271683 | Hayes | Sep 2007 | B2 |
7292125 | Mansour | Nov 2007 | B2 |
8648676 | Abhari | Feb 2014 | B2 |
8754722 | Choi | Jun 2014 | B2 |
Number | Date | Country |
---|---|---|
2796136 | Jul 2006 | CN |
2809911 | Aug 2006 | CN |
101702460 | May 2010 | CN |
202259640 | May 2012 | CN |
Entry |
---|
Li-Yang et al., A Novel Compact Electromagnetic-Bandgap (EBG) Structure and Its Applications for Microwave Circuits, Jan. 2005, IEEE, vol. 53, No. 1, 8 pages. |
Inseop Lim et al., Substrate Integrated Waveguide (SIW) Single Pole Double Throw (SPDT) Switch for X-Band Applications, Aug. 2014, IEEE Microwaves, vol. 24, No. 8, 3 pages. |
Yang Fei et al., Substrate Integrated Waveguide Switch Matrix in LTCC Technology, 2013, Asia-Pacific Microwave Conference Proceedings, P-32, 3 pages. |
Tuncay Erdol, X-Band RF Switch Implementation in Substrate Integrated Waveguide, Sep. 2012, Middle East Technical University, 108 pages. |
Li, Z. et al., “24-GHz Frequency-Modulation Continuous-Wave Radar Front-End System-on-Substrate”, IEEE Transactions on Microwave Theory and Techniques, vol. 56, No. 2, Feb. 2008, pp. 278-285. |
Number | Date | Country | |
---|---|---|---|
20170012335 A1 | Jan 2017 | US |