Reconfigurable electrically tunable filtering phase shifter based on substrate integrated waveguide

Abstract

The invention discloses a reconfigurable electrically tunable filtering phase shifter based on a substrate integrated waveguide, and belongs to the field of filtering phase shifters. The invention discloses a reconfigurable electrically tunable filtering phase shifter based on a substrate integrated waveguide. The reconfigurable electrically tunable filtering phase shifter comprises the substrate integrated waveguide, the open circuit branch knot is used for introducing a transmission zero point at the wide side of the substrate integrated waveguide; one end of the coupling microstrip line is connected with the substrate integrated waveguide; the input and output feeder line is connected with the other end of the coupling microstrip line; and the capacitance regulation and control circuit is connected between the coupling microstrip line and the open-circuit end of the open-circuit branch knot, the capacitance regulation and control circuit connected to the coupling microstrip line is used for controlling phase shift, and the capacitance regulation and control circuit connected to the open-circuit end of the open-circuit branch knot is used for controlling the zero point position. Wherein lumped elements such as the variable capacitance diode and the like are connected in series with the coupling line and the open-circuit end of the open-circuit branch knot, the whole is established on the PCB and has a symmetrical characteristic, and the coupling line and the open-circuit branch knot are symmetrically distributed. The filtering phase shifter has the advantages of reconfigurable bandwidth, filtering passband alignment, continuous and adjustable phase, high precision, miniaturization and the like.

Description

Technical Field

[0001] The present invention relates to the field of filter phase shifters, and in particular to a reconfigurable electrically tunable filter phase shifter based on a substrate integrated waveguide. Background Art

[0002] In systems such as phased arrays, phase shifters are often connected in series with filters at the RF front end, which is not conducive to system miniaturization and integration, and the series connection will increase signal loss. Phase shifters with filtering effects often have the disadvantage of frequency offset, which makes it impossible to align the passband, resulting in reduced frequency selectivity and unfavorable for integrated filtering design. Moreover, with the development of modern phased array and communication systems, facing the development trend of multi-band, phase shifters with reconfigurable characteristics are more suitable for their future development. Reconfigurable characteristics mean that the bandwidth and center frequency of the phase shifter can be controlled, and the phase can be continuously adjusted in different passbands. When facing different frequency band requirements or multi-frequency systems, the passband can be flexibly adjusted to adapt to the system design.

[0003] Reconfigurable, electronically tunable filter phase shifters combine the functions of both filters and phase shifters, and are crucial for miniaturization, integration, and high performance in RF front-end circuits. Traditional filter phase shifters lack independent control over their filter zeros, resulting in passband offset when adjusting the phase. Currently, research on the reconfigurability of filter phase shifters is lacking, and they suffer from high losses and narrow tunable bandwidths. Furthermore, filter phase shifters have been limited to traditional microstrip structures, lacking the exploration of novel architectures. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention proposes a reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide.

[0005] The purpose of the present invention can be achieved through the following technical solutions: The first aspect of the present invention relates to a reconfigurable electrically tunable filter phase shifter based on a substrate integrated waveguide, comprising: substrate integrated waveguide; Open branches are used to integrate the broadside of the waveguide on the substrate and introduce transmission zeros; A coupled microstrip line, one end of which is connected to the substrate integrated waveguide; an input and output feed line connected to the other end of the coupled microstrip line; And, a capacitance control circuit connected to the open end of the coupled microstrip line and the open branch, the capacitance control circuit connected to the coupled microstrip line is used to control the phase shift, and the capacitance control circuit connected to the open end of the open branch is used to control the zero point position.

[0006] Optionally, the capacitance control circuit includes a capacitor C1, an inductor, a varactor diode, and a DC voltage source; the positive electrode of the varactor diode is grounded, and the negative electrode of the varactor diode is connected to one end of the capacitor C1 and one end of the inductor; the other end of the inductor is connected to the DC voltage source; under the action of DC power, the varactor diode can be reverse biased and equivalent to a time-varying capacitor.

[0007] Optionally, one end of the coupling microstrip line is connected to the substrate integrated waveguide through a tapered microstrip line.

[0008] Optionally, the length of the open-circuit branch is one quarter of the wavelength of its resonant frequency.

[0009] Optionally, a metallized grounding through hole is provided at the end of the substrate integrated waveguide.

[0010] Optionally, the substrate integrated waveguide, coupled microstrip line and tapered microstrip line are all made of tinned copper.

[0011] Optionally, the coupled microstrip lines, open branches and capacitance control circuits are all symmetrically distributed.

[0012] Optionally, the coupled microstrip lines, open branches and capacitance control circuits are all symmetrically distributed.

[0013] Optionally, the impedance of the input feeding network and the output feeding network are both 50Ω.

[0014] A second aspect of the present invention relates to a communication device, characterized in that it includes the above-mentioned substrate integrated waveguide-based electrically tunable filter phase shifter.

[0015] A third aspect of the present invention relates to the application of the above-mentioned substrate integrated waveguide-based electrically tunable filter phase shifter in phased array antennas and radars.

[0016] Beneficial effects of the present invention: (1) The present invention adopts a substrate integrated waveguide structure, which has the advantages of low loss and miniaturization. The loss is between 0.88-2.22dB, the geometric center frequency is 1.11GHz, and the equivalent electrical size is 0.166λ g 2 .

[0017] (2) The present invention connects open-circuit branches on the side of the substrate integrated waveguide to introduce two zero points on both sides of the passband. The zero points are independently controlled by the varactor diodes at the open ends and are not subject to interference. The center frequency is fixed at 1.02GHz-1.25GHz, which can achieve 20%-40% bandwidth reconfiguration (maximum 20%-50%) and center frequency reconfiguration of 0.9GHz-1.38GHz, with a tuning fraction of 42.1%.

[0018] (3) The present invention realizes continuous phase adjustment by connecting a varactor diode at the open end of the coupled microstrip line. Since the phase shift and the zero point are independently controlled, the frequency offset will not be caused when the phase is adjusted, and the passband alignment rate can reach more than 91%.

[0019] (4) While achieving frequency / bandwidth reconfiguration, the present invention can achieve a continuous phase shift greater than 60° within each bandwidth, up to a maximum of 160°, and the phase shift error of each passband is ±2.5°~±10°. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 It is a structural schematic diagram of the electrically tunable filtering phase shifter based on substrate integrated waveguide proposed in the present invention.

[0022] Figure 2 It is a top view of the electrically tunable filter phase shifter based on substrate integrated waveguide proposed by the present invention.

[0023] Figure 3 This is a left view of the electrically tunable filter phase shifter based on substrate integrated waveguide proposed by the present invention.

[0024] Figure 4 This is a main view of the electrically tunable filter phase shifter based on substrate integrated waveguide proposed by the present invention.

[0025] Figure 5 The present invention provides a circuit diagram of a varactor diode control circuit for an electrically tunable filter phase shifter based on a substrate integrated waveguide.

[0026] Figures 6 to 10 The transmission characteristics and phase shift curves of the present invention are equally distributed at 0.12 GHz in the center frequency range of 0.9 GHz to 1.38 GHz, wherein (a) is the transmission characteristic curve and return loss curve, and (b) is the phase shift curve.

[0027] Figures 11 to 13 This is a comparison diagram of the present invention at 1.02 GHz, 1.15 GHz, and 1.25 GHz, respectively, while maintaining the center frequency unchanged and changing the working bandwidth. Figure 11 middle, f 0 =1.02GHz bandwidth variation range 20%~40%; Figure 12 middle, f 0 =1.15GHz bandwidth variation range 20%~50%; Figure 13 middle, f 0 =1.25GHz Bandwidth variation range 20%~40% The components corresponding to the numbers in the figure are as follows: 1. Substrate integrated waveguide; 2. Open branch; 2-1. Open branch one; 2-2. Open branch two; 3. Tapered microstrip line; 4. Coupled microstrip line; 5. Input and output feed network; 6-1. Circuit connected to the open end of the coupled microstrip line; 6-2. Circuit connected to the open branch two; 6-3. Circuit connected to the open branch one. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] like Figure 1 、 Figure 2 as well as Figure 3 As shown, the present invention proposes a reconfigurable electrically tunable filter phase shifter based on a substrate integrated waveguide, comprising 1, a substrate integrated waveguide 1, an open branch 1 2-1, an open branch 2-2, a tapered microstrip line 3, a coupling microstrip line 4, an input and output feed line 5, and a capacitance control circuit; the substrate integrated waveguide 1 serves as the main body of the device, and the left and right ends are connected to the coupling microstrip line 4 through the tapered microstrip line 3, and the other end of the coupling microstrip line 4 is connected to the input and output feed line 4.

[0030] At the same time, the open branches are connected to both sides of the substrate integrated waveguide 1, the open branch 1 2-1 is connected to the upper two sides, and the open branch 2-2 is connected to the lower two sides; the open ends of the coupling microstrip line 4 and the open branches are both connected to the varactor diode control circuit.

[0031] Among them, the capacitance control circuit connected to the open end of the coupled microstrip line and the open branch, the capacitance control circuit connected to the coupled microstrip line is used to control the phase shift 6-1, and the capacitance control circuit 6-2 / 6-3 connected to the open end of the open branch is used to control the zero point position.

[0032] The capacitance control circuit specifically includes a capacitor, an inductor, a varactor diode, and a DC voltage. The varactor diode's positive electrode is grounded, while its negative electrode is connected to one end of the capacitor and one end of the inductor. Under the action of the DC voltage, the varactor diode is reverse biased, effectively becoming a time-varying capacitor. In the open-circuit branch and coupled line, the open-circuit ends are connected to capacitor C1, which acts as a DC block.

[0033] The lumped components such as the capacitance control circuit are connected in series with the coupled microstrip line 4 and the open end of the open branch. The whole is built on a dielectric substrate and presents symmetrical characteristics. The coupled microstrip line 4 and the open branch are symmetrically distributed.

[0034] The substrate integrated waveguide 1 is the main body of the phase shifter, with tapered microstrip lines 4 connected at both ends and connected to the coupling microstrip line 4 to enhance coupling and improve transmission efficiency; the two ends of the coupling microstrip line 4 are respectively connected to the input and output feeder lines 5 and the tapered microstrip line 4 to achieve phase shifting while reducing loss; the open-circuit branch is connected to the wide side of the substrate integrated waveguide 1 to introduce a transmission zero point.

[0035] By combining SIW and microstrip, the zero point control and microstrip phase shift are separated, which not only has good passband preservation when adjusting the phase, but also has the characteristics of bandwidth and frequency reconfiguration.

[0036] like Figure 2 、 Figure 3 and Figure 4 As shown, the reconfigurable electrically adjustable filter phase shifter in this example is simulated and tested. The parameters of the tested filter phase shifter are as follows: In some specific embodiments of the present invention, specific design parameters of the phase shifter of the above embodiment are provided, including: the length L1 of the substrate integrated waveguide 1 is 10 mm, the width W1 is 58 mm, and the height H1 is 1.524 mm; the tapered transition structure Wt is 7 mm, Wp is 13 mm, Lt is 10 mm, and Lp is 6 mm; the length Lc of the coupled microstrip line 4 is 7.5 mm, the width Wc is 0.25 mm, and the coupling spacing s is 0.1 mm; the length L2 of the open branch 1 is 10 mm, L3 is 7 mm; the length L4 of the open branch 2-2 is 18 mm, L5 is 8 mm, and L6 is 5 mm; the width of each open branch is W2 is 0.4 mm; the input and output feed network L m =7mm, W m =3.1mm; the through-hole pitch is p=1mm, and the diameter R=0.6mm; the dielectric substrate is Rogers 4003 plate, which has a dielectric constant of 3.38, a thickness of 1.524mm, and a dielectric loss tangent of 0.0027. The impedance of the input and output feed networks 5 is 50Ω.

[0037] The above phase shifter obtained the following results in actual test: Figures 6 to 13 As shown, Figures 6 to 10 Demonstrates center frequency reconfiguration, passband alignment, and filter phase shifting capabilities. The center frequency of each passband f 0 They are 0.9GHz, 1.02GHz, 1.14GHz, 1.26GHz, and 1.38GHz, respectively. According to the data in the figure, the passband maintains a good alignment rate (over 91%), the insertion loss is between 0.89-2.22dB, the return loss is better than 10dB, the phase shift is continuously adjustable over a range of >60°, up to 160°, with an accuracy within ±2.5°~±10°, and the center frequency tuning range is 42.1%; Figure 11 、 Figure 12 、 Figure 13 The bandwidth of the phase shifter is reconfigurable, and the center frequency of each passband is f 0 The test results are 1.02GHz, 1.15GHz, and 1.25GHz, respectively. At a fixed center frequency, at least 20%-40% of the bandwidth can be reconfigured (maximum 20%-50%) within the 1.02GHz-1.25GHz range. Furthermore, four bandwidths, 0°, 30°, 45°, and 60°, are selected to visually demonstrate the passband alignment effect. These test results clearly demonstrate the filter phase shift, reconfigurable frequency / bandwidth, and passband alignment characteristics.

[0038] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0039] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide, characterized in that: include: substrate integrated waveguide; Open branches are used to integrate the broadside of the waveguide on the substrate and introduce transmission zeros; A coupled microstrip line, one end of which is connected to the substrate integrated waveguide; an input and output feed line connected to the other end of the coupled microstrip line; And, a capacitance control circuit connected to the open end of the coupled microstrip line and the open branch, the capacitance control circuit connected to the coupled microstrip line is used to control the phase shift, and the capacitance control circuit connected to the open end of the open branch is used to control the zero point position.

2. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: The capacitance control circuit includes a capacitor C1, an inductor, a varactor diode, and a DC voltage source; the positive electrode of the varactor diode is grounded, and the negative electrode of the varactor diode is connected to one end of the capacitor C1 and one end of the inductor; the other end of the inductor is connected to the DC voltage source; under the action of DC power, the varactor diode can be reverse biased and equivalent to a time-varying capacitor.

3. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: One end of the coupling microstrip line is connected to the substrate integrated waveguide through a tapered microstrip line.

4. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: The length of the open-circuit branch is one quarter of the wavelength of its resonant frequency.

5. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: A metallized grounding through hole is provided at the end of the substrate integrated waveguide.

6. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 3, characterized in that: The substrate integrated waveguide, coupled microstrip line and tapered microstrip line are all made of tinned copper.

7. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: The coupled microstrip lines, open branches and capacitance control circuits are all symmetrically distributed.

8. The reconfigurable electrically tunable filter phase shifter based on substrate integrated waveguide according to claim 1, characterized in that: The coupled microstrip lines, open branches and capacitance control circuits are all symmetrically distributed.

9. A communication device, characterized in that: The invention comprises the electrically tunable filter phase shifter based on substrate integrated waveguide as described in any one of claims 1 to 8.

10. Application of the substrate integrated waveguide-based electrically tunable filter phase shifter according to any one of claims 1 to 8 in phased array antennas and radars.

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