A dielectric filter that can improve far-end crosstalk

Abstract

The application discloses a dielectric filter capable of improving far-end suppression, which comprises a body made of solid dielectric material, a conductive layer coated on the outer surface of the body, a plurality of resonant cavities arranged side by side and opened in the body, and electrode contact surfaces respectively formed at the two ends of the side of the electrode surface of the body close to the circuit surface, wherein the electrode contact surfaces extend to the circuit surface, and after extending to the top, the electrode contact surfaces on the circuit surface are bent downwards to form elongated lines, the bending directions of the two electrode contact surfaces are opposite, and the elongated lines are close to the side surface of the body and extend to the electrode surface. The application can solve the problem of poor far-end suppression of the dielectric filter, and mainly reflects that the harmonic suppression at about 2 times of the center frequency can be obviously improved, and the second harmonic can be pushed to a farther end.

Description

Technical Field

[0001] This application belongs to the field of communication technology, and in particular relates to a dielectric filter that can improve far-end suppression. Background Technology

[0002] Conventional dielectric filters typically exhibit harmonics at less than twice the center frequency, making sufficient suppression in this frequency range virtually impossible. This introduces numerous inconveniences and limitations to product design. Currently, the only solution is to add an additional low-pass filter to meet certain suppression requirements. However, this additional low-pass filter not only increases the filter's insertion loss but also raises manufacturing costs. Different low-pass filter structures can have significantly different prices, and the added space required for the low-pass filter may also increase its overall size, leading to considerable uneconomical design challenges.

[0003] Figure 1 This is a dielectric filter with a center frequency of 3000MHz and a passband of 120MHz. The filter employs a 6-cavity structure and is designed using a dielectric constant of ER10. The designed out-of-band rejection ratio is ≥35dB for the 6000–7000MHz range.

[0004] Simulation results show that the product exhibits a spike at 6163MHz, with the worst suppression being only around 6dB. Furthermore, this suppression is uncontrollable and cannot be significantly improved by adjusting other filter parameters. To meet the 35dB suppression requirement for this frequency band, conventional designs can only achieve this by connecting a dielectric filter in series with a low-pass filter. This problem presents challenges for filter design. Summary of the Invention

[0005] The purpose of this invention is to provide a dielectric filter that can improve far-end suppression, which can solve the problem of poor far-end suppression of dielectric filters. The main improvement is that the harmonic suppression at about twice the center frequency can be significantly improved, and the second harmonic can be pushed to a more distant end.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This application discloses a dielectric filter that can improve far-end suppression, including a body made of solid dielectric material, a conductive layer covering the outer surface of the body, and a plurality of resonant cavities arranged side by side within the body. Electrode contact surfaces are formed at both ends of the electrode surface of the body near the circuit surface. The electrode contact surfaces extend to the circuit surface. The electrode contact surfaces on the circuit surface extend upward and then bend downward to form an extension line. The bending directions of the two electrode contact surfaces are opposite. The extension line is close to the side of the body and extends towards the electrode surface.

[0008] Preferably, in the above-described dielectric filter with improved far-end suppression, the conductive layer covers the inner surface of the resonant cavity.

[0009] Preferably, in the above-described dielectric filter that improves far-end suppression, the resonant cavity is provided in multiple ways.

[0010] Preferably, in the above-described dielectric filter that improves far-end suppression, the two ends of the electrode surface are respectively formed into U-shaped exposed surfaces through a deconductive layer, and the U-shaped exposed surfaces and one edge of the electrode surface together form the electrode contact surface on the electrode surface.

[0011] Preferably, in the above-mentioned dielectric filter that improves far-end suppression, the length of the extension line is obtained through simulation calculation.

[0012] Preferably, in the above-described dielectric filter that improves far-end suppression, the solid dielectric material is ceramic.

[0013] Preferably, in the above-described dielectric filter that improves far-end suppression, the conductive layer is silver.

[0014] Compared with existing technologies, the advantages of this invention are as follows: The circuit design is optimized based on the conventional dielectric filter. Specifically, the silver-plated wires of the input and output electrodes on both sides of the circuit surface are lengthened upwards, bent to both sides, and then extended downwards to a certain length. The bent silver-plated wires (i.e., the extended wires) must extend downwards close to the ground planes on both sides. This can be approximated as adding a dielectric low-pass filter at the input and output ports of the circuit surface. The longer silver-plated wires are approximately equivalent to the inductance in the low-pass circuit. The coupling capacitance formed between the bent, downward-extending silver-plated wires and the ground planes on both sides can be equivalent to the capacitance to ground. The size of this coupling capacitance is related to the distance between the silver-plated wires and the ground planes on both sides; the smaller the distance, the larger the coupling capacitance. This low-pass filter, directly connected in series with the dielectric filter, improves far-end suppression to a certain extent. The length of the silver-plated wires and the distance between the silver-plated wires and the ground planes on both sides can be appropriately calculated through simulation while satisfying far-end suppression requirements. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The image shown is a simulation diagram from the background technology.

[0017] Figure 2 The perspective view of the dielectric filter capable of improving distal suppression in the specific embodiment of the present invention is shown;

[0018] Figure 3 The simulation diagram of the specific embodiment of the present invention is shown. Specific Embodiment

[0019] Next, the technical solutions in the embodiments of the present invention will be described in detail with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0020] Next, a dielectric filter with a center frequency of 3000 MHz and a passband of 120 MHz will be described in detail. The dielectric filter adopts a 6 - cavity structure and is simulated and designed with a dielectric constant of ER10. The out - of - band suppression at the distal end of this model is set to be ≥35 dB in the range of 6000 - 7000 MHz, which is consistent with the index parameters of the conventional scheme.

[0021] As Figure 3 , it can be seen through simulation optimization that the suppression of this dielectric filter at about 2 times the center frequency can meet the requirement of ≥35 dB, and the harmonic suppression at this position has been greatly improved.

[0022] Refer Figure 2 As shown, the dielectric filter capable of improving distal suppression includes a body 100 made of a solid dielectric material, a conductive layer coated on the outer surface of the body 100, and a plurality of resonant cavities 101 arranged side by side and formed inside the body 100. At both ends of one side of the electrode surface 102 of the body 100 close to the circuit surface 103, electrode contact surfaces 104 are respectively formed, and the electrode contact surfaces 104 extend to the circuit surface 103. The electrode contact surfaces 104 on the circuit surface 103 extend upward and then bend downward to form extension lines 105. The bending directions of the two electrode contact surfaces 104 are opposite, and the extension lines 105 are close to the side surface of the body 100 and extend towards the electrode surface 102. The conductive layer coats the inner surface of the resonant cavity 101. There are 6 resonant cavities 101.

[0023] The key to the improved solution is the optimization of the circuit design based on the original conventional dielectric filter. Specifically, the silver-plated wires of the input and output electrodes on both sides of the circuit surface are lengthened upwards, bent to both sides, and then extended downwards to a certain length. The bent silver-plated wires must extend downwards close to the ground planes on both sides. The principle can be approximated as adding a dielectric low-pass filter at the input and output ports of the circuit surface. The longer silver-plated wires are approximately equivalent to the inductance within the low-pass circuit. The coupling capacitance formed between the bent silver-plated wires and the ground planes on both sides can be considered equivalent to the capacitance to ground. The size of this coupling capacitance is related to the distance between the silver-plated wires and the ground planes on both sides; the smaller the distance, the larger the coupling capacitance. This low-pass filter, directly connected in series with the dielectric filter, improves far-end suppression to a certain extent. The length of the silver-plated wires and the distance between the silver-plated wires and the ground planes on both sides can be appropriately calculated through simulation while meeting the requirements of far-end suppression.

[0024] The extended silver-plated wires on both sides of the dielectric filter can be considered equivalent to the inductance L in an LC low-pass circuit. The extended silver-plated wires and the grounded silver layers on both sides form coupling capacitances, equivalent to the capacitance C in an LC low-pass circuit, thus constituting a basic LC low-pass filter. The longer the silver-plated wire, the larger the inductance L, and vice versa; the smaller the distance between the silver-plated wire and the two sides, the larger the coupling capacitance, and vice versa.

[0025] Furthermore, U-shaped exposed surfaces 106 are formed at both ends of the electrode surface 102 through a deconductive layer. The U-shaped exposed surfaces 106 and one edge of the electrode surface 102 form an electrode contact surface 104 on the electrode surface 102.

[0026] Furthermore, the solid dielectric material is ceramic.

[0027] Ceramics have a high dielectric constant, good hardness, and good high-temperature resistance, making them a commonly used solid dielectric material in the field of radio frequency filters.

[0028] Furthermore, the conductive layer is silver.

[0029] The conductive layer is preferably made of a material with high conductivity, such as silver.

[0030] The improved solution can achieve a significant improvement in far-end suppression without increasing the cost or the size of the filter, and does not affect other performance indicators of the dielectric filter. It is simple and convenient to operate and suitable for mass production.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A dielectric filter for improving far-end suppression, comprising a body made of a solid dielectric material, a conductive layer covering the outer surface of the body, and a plurality of resonant cavities arranged side-by-side within the body, wherein electrode contact surfaces are formed at both ends of the electrode surface of the body near the circuit surface, and the electrode contact surfaces extend to the circuit surface, characterized in that, The electrode contact surfaces on the circuit surface extend upwards and then bend downwards to form elongated lines. The bending directions of the two electrode contact surfaces are opposite, and the elongated lines are close to the side of the body and extend towards the electrode surfaces. That is, a dielectric low-pass filter is added at the input and output ports of the circuit surface. The extended line is equivalent to the inductance in the low-pass circuit. The coupling capacitance formed between the extended line extending downward after bending and the ground planes on both sides is equivalent to the capacitance to ground. The size of the coupling capacitance is related to the distance between the extended line and the ground planes on both sides. The smaller the distance, the larger the coupling capacitance. The dielectric low-pass filter is directly connected in series with the dielectric filter to improve the suppression at the far end.

2. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, The conductive layer covers the inner surface of the resonant cavity.

3. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, The resonant cavity is provided in multiple ways.

4. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, Both ends of the electrode surface are formed into U-shaped exposed surfaces through a deconductive layer, and the U-shaped exposed surfaces and one edge of the electrode surface together form the electrode contact surface on the electrode surface.

5. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, The length of the extension line was obtained through simulation calculation.

6. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, The solid dielectric material is ceramic.

7. The dielectric filter with improved far-end suppression according to claim 1, characterized in that, The conductive layer is silver.

Images