Millimeter wave power divider based on electromagnetic bandgap structure
Patent Information
- Application Number
- CN202610909177.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-23
- Publication Date
- 2026-08-28
AI Technical Summary
现有针对SIW+HMSIW功分器的研究中，尚未给出针对深腔体封装条件下腔体寄生震荡问题的有效抑制方案
[0015] The beneficial effects of this invention are as follows: By using a periodic metal column array electromagnetic bandgap structure on the inner surface of the top cover plate of the metal encapsulation cavity, the bandgap covers the operating frequency band, thereby effectively blocking the propagation of parallel plate waveguide modes excited by the deep cavity, thus eliminating parasitic oscillations and significantly improving the transmission response flatness of the power divider in the operating frequency band. At the same time, by using a suspended microstrip line transition structure at the input and output ports, the dielectric loss is reduced by using air dielectric, thereby achieving low insertion loss signal transmission in the millimeter wave band. Furthermore, all structures share the same cavity and dielectric substrate with the power divider body, thus achieving the effect of maintaining the original miniaturization advantage while taking into account low loss and high stability.
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Figure CN122659535A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of millimeter-wave communication and radar technology, and in particular to millimeter-wave power dividers based on electromagnetic bandgap structures. Background Technology
[0002] Power dividers are key passive components in millimeter-wave phased array radars, 5G / 6G communication front-ends, and testing systems. As operating frequencies continue to rise, the radiation and dielectric losses of traditional microstrip power dividers increase significantly. While rectangular waveguide power dividers offer lower losses, they are bulky and difficult to integrate with planar circuits. Substrate integrated waveguides (SIWs) simulate the electric field boundary of a rectangular waveguide by setting two rows of metallized vias on a dielectric substrate, combining the advantages of low loss and planar integration. Half-mode substrate integrated waveguides (HMSIWs) utilize the magnetic walls on the symmetry plane of the SIW to longitudinally halve the waveguide, reducing the lateral dimension by approximately half while maintaining the dominant mode transmission characteristics. A 1-to-2 power divider based on a combined SIW and HMSIW structure can achieve low insertion loss power distribution over a wide frequency band and is one of the commonly used solutions in existing millimeter-wave feed networks.
[0003] In practical engineering applications, millimeter-wave power dividers are typically encapsulated in metal cavities for electromagnetic shielding and mechanical protection. When a SIW+HMSIW 1-to-2 power divider is placed in a deep metal cavity, the following phenomena occur: the in-band insertion loss of the power divider exhibits an abnormal dip, and the port return loss deteriorates significantly, with this phenomenon being more pronounced in the HMSIW region. Existing research on SIW+HMSIW power dividers has not yet provided an effective suppression scheme for the cavity parasitic oscillation problem under deep cavity encapsulation conditions. On the other hand, the input and output interfaces of millimeter-wave power dividers often use direct microstrip line feeding or microstrip line to coaxial connectors, which suffer from high insertion loss in the high-frequency band of millimeter waves. Suspended microstrip lines transmit electromagnetic waves with an air-dielectric hybrid structure, theoretically possessing low transmission loss characteristics; however, a technical solution that simultaneously applies this to the input-output transition of SIW+HMSIW power dividers and combines it with deep cavity encapsulation conditions has not been disclosed in existing technologies. Summary of the Invention
[0004] To address the aforementioned technical problems in related technologies, this invention proposes a millimeter-wave power divider based on an electromagnetic bandgap structure, which can overcome the above-mentioned shortcomings of the prior art.
[0005] To achieve the above-mentioned technical objectives, the technical solution of the present invention is implemented as follows: Millimeter-wave power divider based on electromagnetic bandgap structure; The millimeter-wave power divider based on the electromagnetic bandgap structure includes a dielectric substrate and a power divider body disposed on the dielectric substrate; The power divider body includes a substrate integrated waveguide (SIW) input power stage and a half-mode substrate integrated waveguide (HMSIW) output power stage connected to the output end of the SIW input power stage. A metal encapsulation cavity for accommodating the dielectric substrate and the power divider body, the metal encapsulation cavity including a top cover plate; The electromagnetic bandgap (EBG) resonance suppression structure is a periodic array of metal pillars, each metal pillar is vertically fixed to the inner surface of the top cover plate, and there is an air gap between the lower end face of the metal pillar and the upper surface of the power divider body. The EBG resonance suppression structure is used to suppress the parallel plate waveguide mode excited in the metal package cavity. An input transition structure is connected to the input port of the SIW input power level, and the input transition structure is a suspended microstrip line transition structure; The output transition structure is connected to the two output ports of the HMSIW output power stage, and the output transition structure is a suspended microstrip line transition structure.
[0006] Furthermore, the bandgap range of the periodic metal column array covers the operating frequency band of the power divider body, and its lower cutoff frequency f low With the upper cutoff frequency f high Satisfy the following formula: ; ; in, ; , α∈[0.5,0.8]; c is the speed of light in a vacuum, d is the diameter of the metal column, p is the period of the metal column, and h is the speed of light in a vacuum. c h is the height of the metal column. a The height of the air gap, α, ranges from 0.5 to 0.8, and satisfies f low <f work <f high f work The operating frequency band of the power divider body.
[0007] Furthermore, the characteristic impedance of the suspended microstrip line transition structure is 50 ohms, and its characteristic impedance is determined by the linewidth of the signal conductor, the air gap height, the thickness of the dielectric substrate, and the dielectric constant.
[0008] Furthermore, the SIW input power level is composed of two rows of metallized vias forming an equivalent waveguide wall. The cutoff frequency of the SIW is lower than the lower limit of the operating frequency band, and the spacing between adjacent metallized vias is no more than twice their diameter and no more than one-fifth of the waveguide wavelength of the corresponding operating frequency band.
[0009] Furthermore, the HMSIW output power division forms two mutually symmetrical half-mode waveguide branches by introducing an equivalent magnetic wall at the transverse centerline of the SIW, and the equivalent width of the HMSIW is half the equivalent width of the SIW.
[0010] Furthermore, the output transition structure includes an HMSIW-to-microstrip line matching section and a suspended microstrip line output section connected in sequence. The linewidth and line length of the matching section are set so that the output impedance of the HMSIW output power level matches the characteristic impedance of the suspended microstrip line output section.
[0011] Furthermore, the input transition structure is a suspended microstrip line to coaxial connector structure.
[0012] Furthermore, the periodic metal pillar array is disposed on the inner surface of the top cover plate, and the suspended microstrip line transition structure shares the same dielectric substrate with the SIW input power stage and the HMSIW output power stage, and is integrated into the same metal package cavity.
[0013] Furthermore, the characteristic impedance of the HMSIW output power stage and the characteristic impedance of the SIW input power stage satisfy the following relationship: .
[0014] Furthermore, in the output transition structure, the input impedance of the matching section and the output impedance of the HMSIW output power level meet the matching condition, so that the reflection coefficient is less than -15dB in the operating frequency band.
[0015] The beneficial effects of this invention are as follows: By using a periodic metal column array electromagnetic bandgap structure on the inner surface of the top cover plate of the metal encapsulation cavity, the bandgap covers the operating frequency band, thereby effectively blocking the propagation of parallel plate waveguide modes excited by the deep cavity, thus eliminating parasitic oscillations and significantly improving the transmission response flatness of the power divider in the operating frequency band. At the same time, by using a suspended microstrip line transition structure at the input and output ports, the dielectric loss is reduced by using air dielectric, thereby achieving low insertion loss signal transmission in the millimeter wave band. Furthermore, all structures share the same cavity and dielectric substrate with the power divider body, thus achieving the effect of maintaining the original miniaturization advantage while taking into account low loss and high stability. Attached Figure Description
[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0017] Figure 1 The first simulation diagram of S-parameters without the EBG power divider; Figure 2 The second simulation diagram of S-parameters without the EBG power divider; Figure 3 The first simulation diagram for the S-parameters of the EBG power divider; Figure 4 The second simulation diagram for incorporating the S-parameters of the EBG power divider. Detailed Implementation
[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.
[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0021] According to an embodiment of the present invention, a millimeter-wave power divider based on an electromagnetic bandgap structure includes a dielectric substrate and a power divider body disposed on the dielectric substrate; The power divider body includes a substrate integrated waveguide (SIW) input power stage and a half-mode substrate integrated waveguide (HMSIW) output power stage connected to the output end of the SIW input power stage. A metal encapsulation cavity for accommodating the dielectric substrate and the power divider body, the metal encapsulation cavity including a top cover plate; The electromagnetic bandgap (EBG) resonance suppression structure is a periodic array of metal pillars, each metal pillar is vertically fixed to the inner surface of the top cover plate, and there is an air gap between the lower end face of the metal pillar and the upper surface of the power divider body. The EBG resonance suppression structure is used to suppress the parallel plate waveguide mode excited in the metal package cavity. An input transition structure is connected to the input port of the SIW input power level, and the input transition structure is a suspended microstrip line transition structure; The output transition structure is connected to the two output ports of the HMSIW output power stage, and the output transition structure is a suspended microstrip line transition structure.
[0022] According to an embodiment of the present invention, in a specific implementation of the millimeter-wave power divider based on an electromagnetic bandgap structure, the bandgap range of the periodic metal pillar array covers the operating frequency band of the power divider body, and its lower cutoff frequency f low With the upper cutoff frequency f high Satisfy the following formula: ; ; in, ; , α∈[0.5,0.8]; c is the speed of light in a vacuum, d is the diameter of the metal column, p is the period of the metal column, and h is the speed of light in a vacuum. c h is the height of the metal column. a The height of the air gap, α, ranges from 0.5 to 0.8, and satisfies f low <f work <f high f work The operating frequency band of the power divider body.
[0023] According to an embodiment of the present invention, the millimeter-wave power divider based on an electromagnetic bandgap structure has a characteristic impedance of 50 ohms in a specific implementation of the suspended microstrip line transition structure. The characteristic impedance is determined by the linewidth of the signal conductor, the air gap height, the thickness of the dielectric substrate, and the dielectric constant.
[0024] According to an embodiment of the present invention, the millimeter-wave power divider based on an electromagnetic bandgap structure, in a specific embodiment, the SIW input power divider is composed of two rows of metallized vias forming an equivalent waveguide wall. The cutoff frequency of the SIW is lower than the lower limit of the operating frequency band, and the spacing between adjacent metallized vias is no greater than twice their diameter and no greater than one-fifth of the waveguide wavelength of the corresponding operating frequency band.
[0025] According to an embodiment of the present invention, the millimeter-wave power divider based on an electromagnetic bandgap structure, in a specific implementation, the HMSIW output power divider forms two mutually symmetrical half-mode waveguide branches by introducing an equivalent magnetic wall at the transverse centerline of the SIW, and the equivalent width of the HMSIW is half the equivalent width of the SIW.
[0026] According to an embodiment of the present invention, the millimeter-wave power divider based on an electromagnetic bandgap structure, in a specific embodiment, includes an output transition structure comprising an HMSIW-to-microstrip line matching section and a suspended microstrip line output section connected in sequence. The linewidth and linelength of the matching section are configured such that the output impedance of the HMSIW output power divider matches the characteristic impedance of the suspended microstrip line output section.
[0027] In a specific embodiment of the millimeter-wave power divider based on an electromagnetic bandgap structure according to an embodiment of the present invention, the input transition structure is a suspended microstrip line to coaxial connector structure.
[0028] According to an embodiment of the present invention, in a specific implementation of the millimeter-wave power divider based on an electromagnetic bandgap structure, the periodic metal pillar array is disposed on the inner surface of the top cover plate, and the suspended microstrip line transition structure shares the same dielectric substrate with the SIW input power division and the HMSIW output power division, and is integrated into the same metal package cavity.
[0029] According to an embodiment of the millimeter-wave power divider based on an electromagnetic bandgap structure, in a specific implementation, the characteristic impedance of the HMSIW output power divider and the characteristic impedance of the SIW input power divider satisfy the following relationship: .
[0030] According to an embodiment of the present invention, in a specific implementation of the millimeter-wave power divider based on an electromagnetic bandgap structure, the input impedance of the matching section and the output impedance of the HMSIW output power divider satisfy the matching condition, such that the reflection coefficient is less than -15dB in the operating frequency band.
[0031] To facilitate understanding of the above technical solutions of the present invention, the following detailed description of the above technical solutions of the present invention is provided through specific embodiments and working principles.
[0032] Example A millimeter-wave power divider based on an electromagnetic bandgap structure includes the following components: 1. SIW Input Power Classification Located in the first region of the dielectric substrate, two rows of metallized vias form an equivalent waveguide wall, creating the input port and the first-stage power distribution network. After the signal enters from the input feed port, it is initially evenly distributed through the SIW structure.
[0033] The SIW design must ensure that only the primary mode TE10 is transmitted within the operating frequency band, and its equivalent bandwidth W eff With the diameter d of the metallized through hole via The spacing s satisfies:
[0034] in This is the distance between the centers of the two rows of through holes. The cutoff frequency of the SIW. Approximately
[0035] Design requirements Below the lower limit of the operating frequency band, and the through-hole spacing ,cycle To suppress leakage.
[0036] 2. HMSIW Output Power Classification Connected to the output of the SIW input power distribution, it adopts a half-mode substrate integrated waveguide (HMSIW) structure. By introducing an equivalent magnetic wall at the transverse centerline of the SIW, the complete SIW cavity is cut in half to form two mutually symmetrical half-mode waveguide branches, which are used to further complete the power distribution and transmit signals to the output port.
[0037] The equivalent width of HMSIW is approximately W. HMSIW ≈W eff / 2 Its characteristic impedance Z 0_HMSIW The relationship with SIW can be expressed as:
[0038] The cutoff frequency of an HMSIW is approximately twice that of a SIW with the same structure, resulting in a wider single-mode operating bandwidth. During design, the impedance of the HMSIW output port must be kept on the same order of magnitude as the impedance of the subsequent microstrip matching section. This is typically achieved by adjusting the width of the HMSIW and using a gradient-transition metallized via.
[0039] 3. Electromagnetic bandgap (EBG) resonance suppression structure The EBG structure is a periodic array of metal pillars, each vertically fixed to the inner surface of the top metal cover plate, with an air gap maintained between the lower end face of the metal pillar and the upper surface of the power divider body. This array is arranged above the SIW input power stage and the HMSIW output power stage, forming a two-dimensional electromagnetic bandgap structure.
[0040]
[0041]
[0042] Confirmed, among which By selecting the diameter d, period p, height hc, and gap ha, the band gap can be made to cover the working frequency band.
[0043] Given the diameter d, period p, height hc, and bottom gap ha of the metal pillar array, find the lower bandgap cutoff frequency f of the metal pillar array for the parallel plate waveguide mode. low With the upper cutoff frequency f high satisfy:
[0044]
[0045] in:
[0046] , α∈[0.5,0.8] c is the speed of light in a vacuum. The design constraint is f. low <f work <f high That is, the operating frequency band f of the EBG bandgap coverage power divider. work .
[0047] 4. Suspended microstrip line transition structure Input transition: Connected to the SIW input port, using a suspended microstrip line to coaxial structure. The suspended microstrip line structure is as follows: the signal conductor is located on the upper surface of the dielectric substrate, and the space below the substrate is an air cavity (or partially hollowed out). Its characteristic impedance... The approximate formula is:
[0048] Among them, the effective dielectric constant
[0049] By adjusting the linewidth Ws of the suspended microstrip line and the air gap h air Z0 is designed to be 50Ω to achieve impedance matching with the coaxial connector.
[0050] Output transition: Connected to the ends of the two HMSIW output ports, it includes, in sequence: an HMSIW-to-microstrip line matching section, and a suspended microstrip line output section connected to the matching section. The linewidth Wm and line length Lm of the microstrip matching section are designed to match the output impedance of the HMSIW with the subsequent suspended microstrip line.
[0051] Let the equivalent characteristic impedance of the HMSIW output port be Z. HMSIW The characteristic impedance of the suspended microstrip line is Z. SS The characteristic impedance of the intermediate microstrip matching section is Z. m The propagation constant is βm. The input impedance viewed from the HMSIW port towards the matching section is:
[0052] The matching condition is Zin=Z HMSIW (or the reflection coefficient |Γin| is less than -15dB within the operating frequency band), which is achieved by adjusting Wm and Lm.
[0053] Signal path and working principle: The millimeter-wave signal is input from the coaxial connector and transitions to the SIW input port via a suspended microstrip line. Within the SIW segment, the signal propagates in TE10 mode and, upon reaching the power distribution node, is equally divided into two HMSIW branches. The quasi-TEM mode in each HMSIW branch is converted to microstrip line mode via a microstrip matching section, and then output via a suspended microstrip line, ultimately connecting to the coaxial connector or serving directly as an output port.
[0054] The periodic metal column EBG array set on the inner surface of the top cover plate of the cavity has a bandgap covering the operating frequency band, which blocks the parallel plate waveguide mode excited by the deep cavity, thereby eliminating parasitic oscillations and ensuring the flatness of the power divider's transmission response.
[0055] In summary, by utilizing the above-mentioned technical solution of the present invention, the periodic metal column array electromagnetic bandgap structure disposed on the inner surface of the top cover plate of the metal encapsulation cavity enables its bandgap to cover the operating frequency band, thereby effectively blocking the propagation of parallel plate waveguide modes excited by the deep cavity, thus eliminating parasitic oscillations and significantly improving the transmission response flatness of the power divider in the operating frequency band. At the same time, by using a suspended microstrip line transition structure at the input and output ports, the dielectric loss is reduced by using air dielectric, thereby achieving low insertion loss signal transmission in the millimeter wave band. Furthermore, all structures share the same cavity and dielectric substrate with the power divider body, thereby achieving the effect of maintaining the original miniaturization advantage while taking into account low loss and high stability.
[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A millimeter-wave power divider based on an electromagnetic bandgap structure, characterized in that, Includes a dielectric substrate and a power divider body disposed on the dielectric substrate; The power divider body includes a substrate integrated waveguide (SIW) input power stage and a half-mode substrate integrated waveguide (HMSIW) output power stage connected to the output end of the SIW input power stage. A metal encapsulation cavity for accommodating the dielectric substrate and the power divider body, the metal encapsulation cavity including a top cover plate; The electromagnetic bandgap (EBG) resonance suppression structure is a periodic array of metal pillars, each metal pillar is vertically fixed to the inner surface of the top cover plate, and there is an air gap between the lower end face of the metal pillar and the upper surface of the power divider body. The EBG resonance suppression structure is used to suppress the parallel plate waveguide mode excited in the metal package cavity. An input transition structure is connected to the input port of the SIW input power level, and the input transition structure is a suspended microstrip line transition structure; The output transition structure is connected to the two output ports of the HMSIW output power stage, and the output transition structure is a suspended microstrip line transition structure.
2. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The bandgap range of the periodic metal column array covers the operating frequency band of the power divider body, and its lower cutoff frequency f low With the upper cutoff frequency f high Satisfy the following formula: ； ； in, ； , α∈[0.5,0.8]； c is the speed of light in a vacuum, d is the diameter of the metal column, p is the period of the metal column, and h is the speed of light in a vacuum. c h is the height of the metal column. a The height of the air gap, α, ranges from 0.5 to 0.8, and satisfies f low <f work <f high f work The operating frequency band of the power divider body.
3. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The characteristic impedance of the suspended microstrip line transition structure is 50 ohms, and its characteristic impedance is determined by the linewidth of the signal conductor, the height of the air gap, the thickness of the dielectric substrate, and the dielectric constant.
4. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The SIW input power level is composed of two rows of metallized vias forming an equivalent waveguide wall. The cutoff frequency of the SIW is lower than the lower limit of the operating frequency band, and the spacing between adjacent metallized vias is no more than twice their diameter and no more than one-fifth of the waveguide wavelength of the corresponding operating frequency band.
5. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The HMSIW output power division forms two mutually symmetrical half-mode waveguide branches by introducing an equivalent magnetic wall at the transverse centerline of the SIW, and the equivalent width of the HMSIW is half the equivalent width of the SIW.
6. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The output transition structure includes an HMSIW-to-microstrip line matching section and a suspended microstrip line output section connected in sequence. The linewidth and linelength of the matching section are set so that the output impedance of the HMSIW output power level matches the characteristic impedance of the suspended microstrip line output section.
7. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The input transition structure is a suspended microstrip line to coaxial connector structure.
8. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The periodic metal pillar array is disposed on the inner surface of the top cover plate. The suspended microstrip line transition structure shares the same dielectric substrate with the SIW input power stage and the HMSIW output power stage, and is integrated into the same metal package cavity.
9. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, The characteristic impedance of the HMSIW output power stage and the characteristic impedance of the SIW input power stage satisfy the following relationship: 。 10. The millimeter-wave power divider based on an electromagnetic bandgap structure according to claim 1, characterized in that, In the output transition structure, the input impedance of the matching section and the output impedance of the HMSIW output power level meet the matching condition, so that the reflection coefficient is less than -15dB in the operating frequency band.