A high integration frequency hopping filter using coaxial resonant cavity

Abstract

The application discloses a high-integration frequency hopping filter with coaxial resonant cavities, and belongs to the communication device. In order to solve the problem that the existing frequency hopping filter cannot be miniaturized, the coupling resonant layer comprises two resonant cavities and a coupling window arranged in the middle of the two resonant cavities; the frequency hopping capacitor layer comprises two binary capacitors; the resistance layer comprises two resistance arrays; the resonant inductor layer comprises two inductor arrays; the surface-mounted device layer comprises two groups of device components; the resonant cavities, the binary capacitors, the resistance arrays, the inductor arrays and the device components are arranged in a symmetrical two-column structure; in the layered structure of each column, the resonant cavities and the inductor arrays are arranged in series and connected to the radio frequency input / output ports of the device components, one resistance in each resistance array is connected in series with one diode in the device components to form a single-pole single-throw switch, and is connected with a corresponding ground plate in the binary capacitor to change the capacitance value in the connected circuit. The application is mainly used in the communication field.

Description

Technical Field

[0001] This invention relates to a communication device in the field of electronics, and more particularly to a high-quality, miniaturized, multi-device integrated frequency hopping filter employing a coaxial resonant cavity. Background Technology

[0002] Frequency hopping communication is an important solution in the field of secure communication, with advantages such as anti-interference, anti-interception, and anti-fading. The core hardware supporting frequency hopping communication is the frequency hopping filter.

[0003] Traditional frequency-hopping filters employ a metal cavity structure, integrating filters, capacitor arrays, and various control chips. This type of filter is bulky and heavy, making it unsuitable for use in unmanned systems. However, the emergence of low-temperature co-fired ceramic (LTCC) technology and system-in-package (SiP) technology provides solutions for the manufacturing and packaging of miniaturized devices.

[0004] LTCC technology refers to an electronic module manufacturing technology that involves printing metal paste circuitry onto a green ceramic tape manufactured using a casting method, followed by sintering at a relatively low temperature (below 1000°C) to form a multilayer ceramic circuit board with internal and external conductor circuits. SiP technology refers to the use of technologies such as LTCC to encapsulate complex functional systems composed of various functional chips, passive devices, radio frequency devices, sensors, and power supplies within a single system, thereby achieving high performance and miniaturization.

[0005] Currently, there are generally two approaches to integrated systems using LTCC technology. One approach is to achieve package integration by embedding discrete passive components. This approach requires consideration of the temperature resistance of the embedded components, and the discrete passive components themselves have a certain volume; embedding too many passive components negatively impacts the overall miniaturization of the system. The other approach is to integrate passive components by printing metal circuitry inside the LTCC dielectric material. This approach is suitable for the miniaturized integrated manufacturing of multifunctional and complex systems, but it is limited by the single LTCC material, which greatly restricts its design flexibility and miniaturization capabilities. Summary of the Invention

[0006] To solve the above-mentioned technical problems, this invention provides a highly integrated frequency hopping filter using a coaxial resonant cavity. The system is packaged using LTCC technology and potting encapsulation technology, realizing the integration of active and passive components, and completing the manufacturing of a small, highly integrated frequency hopping filter.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] A highly integrated frequency-hopping filter employing a coaxial resonant cavity includes, from bottom to top, a coupling resonant layer, a frequency-hopping capacitor layer, a resistor layer, a resonant inductor layer, and a surface-mount device layer;

[0009] The coupling resonant layer includes two resonant cavities and a coupling window centrally located between the two resonant cavities; the frequency hopping capacitor layer includes two binary capacitors; the resistor layer includes two resistor arrays; the resonant inductor layer includes two inductor arrays; the surface-mount device layer includes two sets of device components; the resonant cavities, binary capacitors, resistor arrays, inductor arrays, and device components are arranged in a symmetrical two-column structure.

[0010] In each column of layered structures, resonant cavities and inductor arrays are connected in series and connected to the RF input / output ports of the device assembly. A resistor in each resistor array is connected in series with a diode in the device assembly to form a single-pole single-throw switch, and is connected to the corresponding ground plate in the binary capacitor to change the capacitance value in the connected circuit.

[0011] Preferably, the surface-mount device layer includes two symmetrically arranged device assemblies. Each device assembly includes a control chip, several diodes, an RF input / output port, a filling medium, and pads for each surface-mount device. The filling medium has several mounting cavities, and each pad is located on the bottom surface of the mounting cavity. The control chip and several diodes are mounted in the mounting cavity at the top of the filling medium, and the RF input / output port is mounted in the mounting cavity on the outer surface of the filling medium. The anode of each diode is connected to one terminal of a resistor in the resistive layer through a metal line, and the cathode of the diode is grounded through a metal line. The digital output port of the control chip is connected in series to the other terminal of the resistor in the resistive layer.

[0012] Preferably, each resonant cavity includes an inner conductor and an outer conductor, wherein the inner conductor is located inside the outer conductor and the space between them is filled with a filling medium; one end of the inner conductor is connected to the outer conductor and the other end is connected to the inductor array of the resonant inductor layer.

[0013] Preferably, the outer conductor includes an annular top plane, an annular metal column array, and a bottom plane arranged and connected from top to bottom. A wire connecting column is provided on the annular top plane and connected to the grounding port through a metal line.

[0014] Preferably, the inner conductor is a spiral inner conductor, which includes several U-shaped wires and several wire connecting posts. The several U-shaped wires are arranged longitudinally and rotated 90 degrees clockwise or counterclockwise in sequence. Adjacent U-shaped wires are connected by a wire connecting post. A wire connecting post is provided on the topmost U-shaped wire and connected to the inductor array of the resonant inductor layer. A wire connecting post is provided on the bottommost U-shaped wire and connected to the bottom plane. The wire connecting posts are all located at the ends of the U-shaped wires.

[0015] Preferably, each binary capacitor includes several ungrounded plates, several grounded plates, several ungrounded plate electrodes, several grounded plate electrodes, and a second filling medium. The ungrounded plates and grounded plates are arranged alternately in the longitudinal direction and fixed by the second filling medium. The ungrounded plates are connected to each other through ungrounded plate electrodes and connected to the metal lines led out from the inner conductor through metal lines, forming a parallel relationship with the corresponding resonant cavity. Each grounded plate is provided with two grounded plate electrodes, which are connected to the resistor in the resistive layer through metal lines.

[0016] Preferably, each resistor array includes several thick-film resistors, several pairs of resistor electrodes, several pairs of control access electrodes, and a filling dielectric. The thick-film resistors are arranged in a cross pattern to form a grid and are fixed by the filling dielectric. Each thick-film resistor has a pair of resistor electrodes and a pair of control access electrodes at both ends. The lower end of the resistor electrode is connected to the ground electrode of the binary capacitor through a metal line, and the upper end of the resistor electrode is connected to the pad of the positive electrode of the diode through a metal line. The upper end of the control access electrode is connected to the digital output port of the control chip through a metal line.

[0017] Preferably, each inductor array includes two inductor lines, several inductor electrodes, and a filling medium. The two inductor lines are arranged symmetrically and fixed by the filling medium. An inductor electrode is provided at each end of each inductor line. The inductor electrode at one end of the inductor line is connected to the RF input / output port of the surface-mount device layer, and the inductor electrode at the other end of the inductor line is connected to the metal line led out from the inner conductor.

[0018] Preferably, the inductor circuit is composed of a serpentine circuit, a bent circuit, and a conductive connecting post. The serpentine circuit and the bent circuit are arranged longitudinally and connected by the conductive connecting post.

[0019] Preferably, the coupling resonant layer, frequency hopping capacitor layer, resistor layer and resonant inductor layer are all integrally sintered using LTCC technology.

[0020] The beneficial effects of this invention compared to the prior art are:

[0021] 1. The coupling resonant layer, frequency hopping capacitor layer, resistor layer, and resonant inductor layer of this invention are integrated into a single system using LTCC technology. A heterogeneous co-firing scheme is employed to improve system design flexibility, solve the problem of integrating complex device functions, and enhance the system's anti-interference and anti-crosstalk capabilities. Different functional layers can use different substrate materials to reduce filter size, or they can use the same substrate material for ease of manufacturing. The surface-mount device layer uses potting encapsulation technology to completely encapsulate the devices integrated on the surface of the LTCC dielectric material, making it a single, integrated frequency hopping filter.

[0022] 2. In this invention, multiple functional devices are integrated into a single LTCC package system, minimizing module size and weight, improving system portability, and providing good adaptability to low-load systems.

[0023] 3. The coupling resonant layer of this invention employs an internal spiral resonant cavity structure, which significantly reduces the resonant frequency of the cavity and effectively reduces the size of the coaxial resonant cavity, thus achieving miniaturization of the frequency hopping filter. Furthermore, the resonant cavity structure used in this application has a higher quality factor than LC resonant circuits, which is beneficial for improving the performance of the frequency hopping system.

[0024] 4. In the coupling resonant layer of the present invention, the outer conductor adopts a metal pillar array instead of an external metallization scheme, which is more suitable for LTCC process applications. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are provided to further illustrate the invention.

[0026] Figure 1 This is a block diagram of the overall structure of the present invention.

[0027] Figure 2 This is a schematic diagram of the overall structural model of the present invention.

[0028] Figure 3 This is a top-view cross-sectional view of the coupled resonant layer.

[0029] Figure 4 This is a vertical cross-sectional view of the coupled resonant layer.

[0030] Figure 5 This is a schematic diagram of the inner conductor.

[0031] Figure 6 This is a schematic diagram of the structure of the frequency hopping capacitor layer.

[0032] Figure 7 This is a schematic diagram of the resistive layer structure.

[0033] Figure 8 This is a schematic diagram of the resonant inductor layer.

[0034] Figure 9 This is a schematic diagram of the structure of a surface-mount device layer.

[0035] Figure 10 The following are the S-parameter simulation results of the frequency hopping filter in the embodiment.

[0036] Figure reference numerals: 100 - Coupled resonant layer; 110 - Resonant cavity; 111 - Inner conductor; 1111 - U-shaped wire; 1112 - Wire connecting post; 112 - Outer conductor; 1121 - Annular top plane; 1122 - Annular metal pillar array; 1123 - Bottom plane; 113 - Filling medium one; 120 - Coupling window; 200 - Frequency hopping capacitor layer; 210 - Binary capacitor; 211 - Ungrounded electrode; 212 - Grounded electrode; 213 - Ungrounded electrode; 214 - Grounded electrode; 215 - Filling medium two; 300 - Resistor layer; 310 Resistor array; 311 Thick film resistor; 312 Resistor electrode; 313 Control access electrode; 314 Filling dielectric three; 400 Resonant inductor layer; 410 Inductor array; 411 Inductor circuit; 4111 Serpentine circuit; 4112 Bent circuit; 4113 Conductive connection post; 412 Inductor electrode; 413 Filling dielectric four; 500 Surface mount device layer; 510 Device assembly; 511 Control chip; 512 Diode; 513 RF input / output port; 514 Filling dielectric five. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0038] See Figure 1 and Figure 2This application provides a highly integrated frequency-hopping filter using a coaxial resonant cavity, comprising, from bottom to top, a coupling resonant layer 100, a frequency-hopping capacitor layer 200, a resistor layer 300, a resonant inductor layer 400, and a surface-mount device layer 500. Each of these components consists of two symmetrically arranged structures, forming two columns of symmetrical layered structures in the filter. The layered structures in the same column are connected by longitudinal metal lines. The coupling resonant layer 100 and the resonant inductor layer 400 are connected in series and connected to the RF input / output port of the surface-mount device layer 500. The frequency-hopping capacitor layer 200 and the resistor layer 300 are connected in series and connected to the diode of the surface-mount device layer 500. The coupling resonant layer 100 and the frequency-hopping capacitor layer 200 are connected in parallel, forming the basic structure of the filter.

[0039] like Figure 9 As shown, the surface mount device layer 500 includes two symmetrically arranged device assemblies 510. Each device assembly 510 includes a control chip 511, several diodes 512, an RF input / output port 513, a filling medium 514, and pads and circuit traces for each surface mount device. Several mounting cavities reserved for surface mount devices are provided on the filling medium 514 of the surface mount device layer 500. Each pad is located on the bottom surface of the mounting cavity within the filling medium 514 and is made of copper, silver, or other suitable conductive materials. The control chip 511 and several diodes 512 are mounted within the mounting cavities of the filling medium 514, while the RF input / output port 513 and other ports are mounted in mounting cavities on the outer surface of the filling medium 514. Each surface mount device uses gold wire bonding technology to connect the pads on the semiconductor chip die to the pads on the filling medium. The positive pad of each diode 512 is connected to one terminal of a resistor in the resistor layer 300 via a metal line, and the negative pad of the diode 512 is grounded via a metal line. After the digital output port of the control chip 511, a resistor in the resistor layer 300 is connected in series, followed by a diode 512, and then grounded. The grounding plate of the binary capacitor is connected between the resistor and the diode. When the diode is forward-biased, the grounding plate of the binary capacitor is grounded, and the capacitor is connected to the circuit. The power supply pins, grounding pins, etc., of the control chip 511 are led out to their respective ports via metal lines. Finally, using potting encapsulation technology, potting compound is filled into the cavity of the surface mount device layer's filling medium. After the potting compound cures at room temperature or with heating, the manufacturing of the frequency hopping filter of this invention is completed.

[0040] In this embodiment, one set of device components 510 is configured as an RF input port, and the other set of device components 510 is configured as an RF output port, with a corresponding layered structure connected to the corresponding port.

[0041] like Figure 3 , Figure 4 and Figure 5 As shown, the coupled resonant layer 100 includes two symmetrically arranged resonant cavities 110 and a coupling window 120 centrally located between the two resonant cavities 110. The two resonant cavities 110 form an integrated coupled resonant structure through the coupling window 120. The dimensions of the coupled resonant layer 100 are 14*7*5.8mm, and the dimensions of a single resonant cavity 110 are 7*6.8*5.8mm.

[0042] Each resonant cavity 110 includes an inner conductor 111 and an outer conductor 112, wherein the inner conductor 111 is located inside the outer conductor 112 and the space between them is filled with a filling medium 113; one end of the inner conductor 111 is connected to the outer conductor 112, and the other end is connected to the resonant inductor layer 400 through a metal line, wherein the inner conductor 111 and the outer conductor 112 are made of copper, silver or other suitable conductive materials, and the filling medium 113 is made of a dielectric ceramic material with a dielectric constant of 80.

[0043] Furthermore, since LTCC technology has difficulty obtaining a large area of ​​vertical metal layer inside the dielectric, the metal layer can only be plated onto the dielectric surface in subsequent processing, which adds extra processes. Moreover, the exposed metal layer is more prone to wear, which has an adverse effect on device performance. Therefore, the outer conductor 112 adopts the form of a metal pillar array, which includes an annular top plane 1121, an annular metal pillar array 1122 and a bottom plane 1123 arranged and connected from top to bottom. A wire connection post is provided on the annular top plane 1121 and connected to the grounding port through a metal line.

[0044] Furthermore, the annular metal column array 1122 is a 5.4*5.4mm square, which is composed of several metal columns with a diameter of 0.4mm and a length of 5mm. The distance between two adjacent metal columns is 0.2mm, and the metal column adjacent to the coupling window 120 has a 0.8mm gap in the middle.

[0045] Furthermore, to reduce the volume of the coupling resonant layer 100, the inner conductor 111 is a spiral inner conductor, which includes several U-shaped wires 1111 and several wire connecting posts 1112. The several U-shaped wires 1111 are arranged longitudinally and rotated 90 degrees clockwise or counterclockwise in sequence. Adjacent U-shaped wires 1111 are connected by a wire connecting post 1112. A longer wire connecting post 1112 is provided on the topmost U-shaped wire 1111. The longer wire connecting post 1112 is connected to the resonant inductor layer 400 through a metal wire passing through the annular top plane 1121. A wire connecting post 1112 is provided on the bottommost U-shaped wire 1111 and connected to the bottom plane 1123. The wire connecting posts 1112 are all located at the ends of the U-shaped wires 1111.

[0046] Furthermore, the U-shaped conductor 1111 has a line width of 0.4 mm and a thickness of 20 μm, the conductor connecting post 1112 has a diameter of 0.4 mm and a length of 0.18 mm, and the spiral inner conductor has 23 layers with an inner diameter of 2.4 mm.

[0047] Furthermore, the coupling window 120 has a width of 1.2 mm, a thickness of 0.4 mm, and a resonant frequency of 1.97 GHz.

[0048] In this embodiment, the coupling resonant layer 100 is obtained using LTCC technology, and the specific fabrication process is as follows:

[0049] Step 1: Use tape casting technology to create green ceramic tape;

[0050] Step 2: Design the screen design using drawing software;

[0051] Step 3: Punch holes on the green ceramic tape using the drawn stencil pattern: Drill through holes on the green ceramic tape according to the layout of each stencil pattern to form the first through hole of the metal pillar in the outer conductor 112 and the second through hole of the wire connecting pillar 1112 in the inner conductor 111.

[0052] Step 4: Inject metal slurry into the through hole 2 of each green ceramic strip to form wire connection post 1112;

[0053] Step 5: Using screen printing technology, the corresponding conductive circuits are printed on each green ceramic film according to the circuit diagrams drawn on different screens, to obtain U-shaped wires 1111, annular top plane 1121 and bottom plane 1123.

[0054] Step 6: Stack the green ceramic films into a three-dimensional preform;

[0055] Step 7: On the three-dimensional blank, a notch is opened at the opposite position between the two resonant cavities 110, and a coupling window 120 is formed at the connection between the two notches.

[0056] Step 8: Inject metal slurry into the through hole one of the three-dimensional blank, and after drying, form a metal column.

[0057] like Figure 6 As shown, the frequency hopping capacitor layer 200 uses binary capacitors to realize the function of changing the capacitance value, and includes two symmetrically arranged and integrally formed binary capacitors 210.

[0058] Each binary capacitor 210 includes several ungrounded plates 211, several grounded plates 212, several ungrounded plate electrodes 213, several grounded plate electrodes 214, and a second filling medium 215. The ungrounded plates 211 and grounded plates 212 are arranged alternately in the longitudinal direction and fixed by the second filling medium 215. Each plate and the filling medium form a parallel plate capacitor, with electrodes distributed at the edges of each plate. By connecting different plates to the circuit, the capacitance value is changed, thereby realizing the frequency hopping function of the filter. The ungrounded plates 211 are connected to each other through ungrounded plate electrodes 213 and connected to the metal lines led out from the inner conductor 111 through metal lines, forming a parallel relationship with the corresponding resonant cavity 110. Each grounded plate 212 is provided with two grounded plate electrodes 214 and is connected to the resistive layer 300 through metal lines.

[0059] Furthermore, both the ungrounded electrode 211 and the grounded electrode 212 are metal plates made of copper, silver, or other suitable conductive materials, and the distance between two adjacent electrodes is 0.2 mm; both the ungrounded electrode 213 and the grounded electrode 214 are made of copper, silver, or other suitable conductive materials, and the filling medium 215 is made of various dielectric materials suitable for LTCC processing technology and is determined by capacitance parameters.

[0060] In this embodiment, if each binary capacitor 210 has 10 frequency hopping points, then there are 4 grounding plates 212 and 3 non-grounding plates 211, with each grounding plate having an area of ​​2mm². 2 4mm 2 8mm 2 and 16mm 2The dielectric constant of the filling medium 215 is 3.2. The capacitance values ​​formed between the adjacent grounding plates 212 and the ungrounding plates 211 are 0.56pF, 1.12pF, 2.24pF, and 4.48pF, respectively. By connecting different grounding plates 212 to the circuit, the capacitance values ​​of the binary capacitors 210 can reach 16, and the capacitance value range connected to the circuit can reach 0-8.4pF. Selecting 10 capacitance values ​​can meet the requirements of 10 frequency hopping points.

[0061] In this embodiment, the frequency hopping capacitor layer 200 is obtained using LTCC technology, and the specific fabrication process is as follows:

[0062] Step 1: Use tape casting technology to create green ceramic tape;

[0063] Step 2: Design the screen design using drawing software;

[0064] Step 3: Punch holes in the green ceramic tape using the drawn mesh pattern: Drill through holes in the green ceramic tape according to the layout of each mesh pattern to obtain the non-grounded electrode 213 and the grounded electrode 214.

[0065] Step 4: Inject metal slurry into the through holes of each green ceramic strip to form a non-grounded electrode 213 and a grounded electrode 214;

[0066] Step 5: Using screen printing technology, the corresponding conductive circuits are printed on each green ceramic film according to the circuit diagrams drawn on different screen patterns to obtain the non-grounded electrode plate 211 and the grounded electrode plate 212.

[0067] Step 6: Stack the green ceramic films into a three-dimensional embryo.

[0068] like Figure 7 As shown, the resistor layer 300 mainly serves to limit current and prevent the diode from burning out. It includes two integrally formed and symmetrically arranged resistor arrays 310.

[0069] Each resistor array 310 includes several thick-film resistors 311, several pairs of resistor electrodes 312, several pairs of control access electrodes 313, and a filling dielectric 314. The thick-film resistors 311 are arranged in a cross pattern to form a grid and are fixed by the filling dielectric 314. Each thick-film resistor 311 has a pair of resistor electrodes 312 and a pair of control access electrodes 313 at each end. The lower end of the resistor electrode 312 is connected to the ground electrode 214 of the binary capacitor 210 through a metal line, and the upper end of the resistor electrode 312 is connected to the pad of the positive electrode of the diode 512 through a metal line. The upper end of the control access electrode 313 is connected to the digital output port of the control chip 511 through a metal line.

[0070] In this embodiment, there are four thick-film resistors 311. Each thick-film resistor 311 is connected in series with a diode 512 to form a single-pole single-throw switch, forming a total of four single-pole single-throw switches. These switches are configured one-to-one with the four grounding plates 212 in the binary capacitor 210. Each single-pole single-throw switch receives a signal from the control chip 511 to control whether each grounding plate 212 in the binary capacitor 210 is connected to the circuit, thereby changing the capacitance value in the circuit.

[0071] In this embodiment, the resistance value of each thick film resistor 311 is 250Ω, and the size of the thick film resistor 311 is 4*1.6mm. The R-12T paste (sheet resistance of 100Ω / □) from Xi'an Xinbei Electronic Technology Co., Ltd. can be selected.

[0072] In this embodiment, the resistive layer 300 is obtained using LTCC technology, and the specific fabrication process is as follows:

[0073] Step 1: Use tape casting technology to create green ceramic tape;

[0074] Step 2: Design the screen design using drawing software;

[0075] Step 3: Punch holes in the green ceramic tape using the drawn stencil pattern: Drill through holes in the green ceramic tape according to the layout of each stencil pattern to obtain the resistance electrode 312 and the control access electrode 313.

[0076] Step 4: Inject metal paste into the through holes of each green ceramic strip to form a resistance electrode 312 and a control access electrode 313;

[0077] Step 5: The resistor material is a paste. First, the required resistor pattern is processed on the green ceramic tape. Then, during the LTCC process of stacking green ceramic sheets, the resistor paste is poured into the position of each resistor.

[0078] like Figure 8 As shown, the resonant inductor layer 400 includes two symmetrically arranged and integrally formed inductor arrays 410. Each inductor array 410 includes two inductor lines 411, a plurality of inductor electrodes 412, and a filling dielectric 413. The two inductor lines 411 are symmetrically arranged and fixed by the filling dielectric 413. Each inductor line 411 has an inductor electrode 412 at each end. One end of the inductor electrode 412 of the inductor line 411 is connected to the RF input / output port 513 of the surface mount device layer 500, and the other end of the inductor electrode 412 is connected to the metal line led out from the inner conductor 111. The inductor lines 411 are made of copper, silver, or other suitable conductive materials, and the filling dielectric 413 is made of various dielectric materials suitable for LTCC processing.

[0079] Furthermore, the inductor circuit 411 is composed of a serpentine circuit 4111, a bent circuit 4112, and a conductive connecting post 4113. The serpentine circuit 4111 and the bent circuit 4112 are arranged longitudinally and connected by the conductive connecting post 4113.

[0080] In this embodiment, the resonant inductor layer 400 is obtained using LTCC technology, and various suitable LTCC inductor structures can be adopted according to the required inductance value and size limitations. The inductor in this embodiment is a planar serpentine inductor, with one pole connected to the RF input / output port and the other pole connected before the frequency hopping capacitor and the switch. The inductance value connected to the circuit is 7nH.

[0081] In this embodiment, the frequency-hopping filter is manufactured using LTCC technology. Except for the surface-mount device layer 500, all other components are integrally formed during the LTCC sintering process. The filling medium between each layer can be of different materials, selected according to requirements. The thickness of each substrate green ceramic sheet is 10-200 μm, and the thickness of the planar metal lines, such as capacitor plates, is 1-100 μm. Each metal part and resistor can be pre-shaped by drilling and etching on the LTCC dielectric green sheet, then layering the green sheets, filling with paste, drying, and finally sintering. The co-firing of multiple heterogeneous materials (the structural diagram is for illustrative purposes only and does not represent that each layer is manufactured separately) improves the flexibility of system design, solves the problem of integrating complex device functions, and improves the system's anti-interference and anti-crosstalk capabilities. After sintering, SMT surface mount technology or die-on-chip packaging technology is used to integrate each surface-mount device onto the system surface.

[0082] The frequency hopping filter in this embodiment has an overall size of 14*7*9mm, which realizes the miniaturization of the frequency hopping filter.

[0083] like Figure 10 As shown in the simulation results of the S-parameters in this embodiment, when the inductance of the resonant inductor is 7nH and the capacitance of the capacitor array connected to the circuit is 6.2pF, the center frequency of the frequency hopping filter of this invention is 1.8GHz, the return loss -10dB bandwidth is 20MHz, the in-band insertion loss is no greater than 4dB, and the in-band return loss is no greater than -10dB. By changing the capacitance value of the connected circuit, the center frequency can jump between 1.75GHz and 1.9GHz.

[0084] By adjusting the structure and size of the inner and outer spiral conductors in the resonant cavity, the value of the resonant inductance, and the number and area of ​​the plates of the binary capacitor, a frequency hopping filter that can operate in the required frequency band between 200MHz and 6GHz can be obtained.

[0085] In summary, the key technical indicators involved in this invention are as follows:

[0086] Operating frequency range: can be selected arbitrarily from 200MHz to 6GHz depending on the requirements;

[0087] Operating bandwidth: 10MHz-20MHz;

[0088] In-band insertion loss: not greater than 5dB;

[0089] In-band return loss: not greater than -10dB;

[0090] Number of frequency hopping points: more than 2, with no upper limit | (set according to requirements).

[0091] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A highly integrated frequency-hopping filter employing a coaxial resonant cavity, characterized in that: It comprises, from bottom to top, a coupling resonant layer (100), a frequency hopping capacitor layer (200), a resistor layer (300), a resonant inductor layer (400), and a surface-mount device layer (500); the coupling resonant layer (100), the frequency hopping capacitor layer (200), the resistor layer (300), and the resonant inductor layer (400) are all integrally sintered using LTCC technology; the surface-mount device layer is obtained using potting encapsulation technology; The coupling resonant layer (100) includes two resonant cavities (110) and a coupling window (120) centrally located between the two resonant cavities (110); the frequency hopping capacitor layer (200) includes two binary capacitors (210); the resistor layer (300) includes two resistor arrays (310); the resonant inductor layer (400) includes two inductor arrays (410); the surface-mount device layer (500) includes two sets of device assemblies (510); the resonant cavities (110), binary capacitors (210), resistor arrays (310), inductor arrays (410), and device assemblies (510) are arranged in a symmetrical two-column structure; In each column of the layered structure, the resonant cavity (110) and the inductor array (410) are connected in series and connected to the RF input / output port of the device assembly (510). A resistor in each resistor array (310) is connected in series with a diode in the device assembly (510) to form a single-pole single-throw switch and is connected to the corresponding ground plate in the binary capacitor (210) to change the capacitance value in the connected circuit.

2. The high-integration frequency-hopping filter using a coaxial resonant cavity according to claim 1, characterized in that: The surface mount device layer (500) includes two symmetrically arranged device assemblies (510). Each device assembly (510) includes a control chip (511), several diodes (512), an RF input / output port (513), a filling medium (514), and pads for each surface mount device. The filling medium (514) has several mounting cavities, and each pad is located on the bottom surface of the mounting cavity. The control chip (511) and several diodes (512) are mounted in the mounting cavity at the top of the filling medium (514), and the RF input / output port (513) is mounted in the mounting cavity on the outer surface of the filling medium (514). The positive terminal of each diode (512) is connected to one pole of a resistor in the resistor layer (300) through a metal line, and the negative terminal of the diode (512) is grounded through a metal line. The digital output port of the control chip (511) is connected in series to the other pole of a resistor in the resistor layer (300).

3. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 1, characterized in that: Each resonant cavity (110) includes an inner conductor (111) and an outer conductor (112), wherein the inner conductor (111) is located inside the outer conductor (112) and the two are filled with a filling medium (113); one end of the inner conductor (111) is connected to the outer conductor (112) and the other end is connected to the inductor array (410) of the resonant inductor layer (400).

4. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 3, characterized in that: The outer conductor (112) includes an annular top plane (1121), an annular metal column array (1122), and a bottom plane (1123) arranged and connected together from top to bottom. A wire connection post is provided on the annular top plane (1121) and connected to the grounding port through a metal line.

5. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 4, characterized in that: The inner conductor (111) is a spiral inner conductor, which includes several U-shaped wires (1111) and several wire connecting posts (1112). The several U-shaped wires (1111) are arranged longitudinally and rotated 90 degrees clockwise or counterclockwise in sequence. Two adjacent U-shaped wires (1111) are connected by a wire connecting post (1112). A wire connecting post (1112) is provided on the topmost U-shaped wire (1111) and connected to the inductor array (410) of the resonant inductor layer (400). A wire connecting post (1112) is provided on the bottommost U-shaped wire (1111) and connected to the bottom plane (1123). The wire connecting posts (1112) are all located at the ends of the U-shaped wires (1111).

6. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 3, characterized in that: Each binary capacitor (210) includes several ungrounded plates (211), several grounded plates (212), several ungrounded plate electrodes (213), several grounded plate electrodes (214), and a second filling medium (215). The ungrounded plates (211) and grounded plates (212) are arranged alternately in the longitudinal direction and fixed by the second filling medium (215). The ungrounded plates (211) are connected to each other through ungrounded plate electrodes (213) and connected to the metal lines led out from the inner conductor (111) through metal lines, forming a parallel relationship with the corresponding resonant cavity (110). Each grounded plate (212) is provided with two grounded plate electrodes (214) and is connected to the resistor in the resistor layer (300) through metal lines.

7. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 6, characterized in that: Each resistor array (310) includes several thick film resistors (311), several pairs of resistor electrodes (312), several pairs of control access electrodes (313), and a filling dielectric (314); several thick film resistors (311) are arranged in a cross pattern to form a grid, and are fixed by the filling dielectric (314); each thick film resistor (311) has a pair of resistor electrodes (312) and a pair of control access electrodes (313) at both ends; the lower end of the resistor electrode (312) is connected to the ground plate electrode (214) of the binary capacitor (210) through a metal line, and the upper end of the resistor electrode (312) is connected to the pad of the positive electrode of the diode (512) through a metal line; the upper end of the control access electrode (313) is connected to the digital output port of the control chip (511) through a metal line.

8. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 3, characterized in that: Each inductor array (410) includes two inductor lines (411), several inductor electrodes (412), and a filling medium (413). The two inductor lines (411) are arranged symmetrically and fixed by the filling medium (413). Each inductor line (411) has an inductor electrode (412) at both ends. The inductor electrode (412) at one end of the inductor line (411) is connected to the RF input / output port (513) of the surface mount device layer (500), and the inductor electrode (412) at the other end of the inductor line (411) is connected to the metal line led out from the inner conductor (111).

9. A highly integrated frequency-hopping filter employing a coaxial resonant cavity according to claim 8, characterized in that: The inductor circuit (411) is composed of a serpentine circuit (4111), a bent circuit (4112), and a conductive connecting post (4113). The serpentine circuit (4111) and the bent circuit (4112) are arranged longitudinally and connected by the conductive connecting post (4113).

Images