Broadband equalization circuit based on microstrip ring resonator and tunable lumped elements

Abstract

The application discloses a wideband equalization circuit based on microstrip ring resonators and adjustable lumped elements, and belongs to the technical field of radio frequency communication. The circuit comprises i microstrip ring resonators and adjustable lumped elements connected across the microstrip ring resonators, wherein i is greater than or equal to 1 and is a positive integer; the microstrip ring resonators are connected through microstrip lines, and the first and last two microstrip ring resonators are connected with an input port and an output port through microstrip lines. The application connects adjustable lumped elements across the microstrip ring resonators, and realizes multiple adjustments of the working frequency, working bandwidth and amplitude equalization of the circuit through impedance adjustment of the adjustable lumped elements, which is beneficial to multifunctional and reconfigurable design of equipment. In addition, the whole circuit structure is simple and can meet the requirements of miniaturization and light weight of equipment.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology, and in particular to a broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements. Background Technology

[0002] In applications such as radar, communication, navigation, and reconnaissance, strict requirements are placed on the in-band amplitude of transmitted signals to achieve system performance targets. Excessive amplitude can cause signal distortion, thereby degrading system performance. A common solution is to add an equalization circuit to the signal transmission link, whose amplitude fluctuation characteristics are opposite to those of the transmitted signal, thus reducing amplitude fluctuations. With the increasing broadband nature of systems and the integration of equipment, achieving equalization processing of broadband signals has become an urgent problem to be solved in current engineering applications.

[0003] Most existing amplitude equalization circuits are composed of resonator units, such as cavity resonators and microstrip resonators. The size of cavity resonators is wavelength-dependent, making it difficult to meet the requirements of miniaturized and lightweight devices. Microstrip resonators have a narrow operating bandwidth, which is insufficient for broadband applications.

[0004] The adjustability of the equalizer's operating frequency and equalization level is another key concern in broadband applications. Existing adjustable equalizer circuits typically use PIN diodes to change the circuit's frequency, equalization level, and other characteristics, with electronic adjustment being the common method of adjustment. However, the amplitude-frequency response of equalizer circuits mostly exhibits monotonically increasing or decreasing characteristics, making it difficult to adapt to the requirements of multi-band applications, and thus limiting their adjustability. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of the prior art and provide a broadband equalization circuit based on a microstrip ring resonator and an adjustable lumped element.

[0006] The objective of this invention is achieved through the following technical solution: a broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements, the broadband equalization circuit comprising:

[0007] i microstrip ring resonators and an adjustable lumped element connected across each microstrip ring resonator, where i ≥ 1 and is a positive integer; the microstrip ring resonators are connected to each other via microstrip lines, and the two microstrip ring resonators at the beginning and end are connected to the input port and the output port via microstrip lines, respectively.

[0008] In one example, the adjustable lumped element is any one or more of an adjustable resistor, an adjustable inductor, and an adjustable capacitor, used for impedance adjustment.

[0009] In one example, the adjustable lumped element is an adjustable resistor, an adjustable inductor, and an adjustable capacitor connected in parallel.

[0010] In one example, the adjustable resistor has a resistance range of 0 Ohm to 1000 Ohm; the adjustable capacitor has a capacitance range of 0.5pF to 100pF.

[0011] In one example, the impedance adjustment method of the adjustable ensemble element is any one or more of electrical adjustment, mechanical adjustment, and magnetic field adjustment.

[0012] In one example, the input port, output port, and microstrip line all have the same impedance.

[0013] In one example, the impedance of the input port, output port, and microstrip line is all 50 Ohm.

[0014] In one example, when the circuit includes two microstrip ring resonators, the transfer matrix of the circuit is:

[0015]

[0016] Z1 and Z2 are the complex impedances of the two microstrip ring resonators, respectively.

[0017] In one example, the insertion loss S of the circuit 21 for:

[0018]

[0019] Where Z0 is the characteristic impedance of the transmission line.

[0020] In one example, the insertion loss S 21 The amplitude is:

[0021]

[0022] When the two microstrip ring resonators resonate at frequencies ω1 and ω2 respectively, the insertion loss S 21 The amplitudes have minimum values ​​at frequencies ω1 and ω2, thus achieving amplitude equalization in at least two frequency bands.

[0023] It should be further noted that the technical features corresponding to the above examples can be combined or substituted to form new technical solutions.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention connects an adjustable lumped element across a microstrip ring resonator. By adjusting the impedance of the adjustable lumped element, multiple adjustments can be made to the circuit's operating frequency, operating bandwidth, and amplitude equalization. This is highly beneficial for the integrated and reconfigurable design of multifunctional equipment. In addition, the entire circuit structure is simple and can meet the needs of miniaturized and lightweight equipment. Attached Figure Description

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, which are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to denote the same or similar parts. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0027] Figure 1 This is a diagram of an equalization circuit in one example of the present invention;

[0028] Figure 2 A preferred example of the equalization circuit diagram of the present invention;

[0029] Figure 3 This is a schematic diagram of the insertion loss obtained by adjusting capacitor C1 in a preferred example equalization circuit model of the present invention.

[0030] Figure 4 This is a schematic diagram of the return loss obtained by adjusting capacitor C1 in a preferred example equalization circuit model of the present invention.

[0031] Figure 5 This is a schematic diagram of the insertion loss obtained by adjusting resistor R1 in a preferred example equalization circuit model of the present invention.

[0032] Figure 6 This is a schematic diagram of the return loss obtained by adjusting resistor R1 in the preferred example equalization circuit model of the present invention.

[0033] In the diagram: 1-Input port, 2-First microstrip line, 3-First adjustable lumped element, 4-Second microstrip line, 5-First microstrip ring resonator, 6-Second adjustable lumped element, 7-Second microstrip ring resonator, 8-Third microstrip line, 9-Output port. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0035] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description. They 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, and therefore should not be construed as limiting this invention. Furthermore, the use of ordinal numbers (e.g., "first and second," "first to fourth," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] In one example, a broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements, such as Figure 1 As shown, the broadband equalization circuit specifically includes an input port and i microstrip ring resonators m1 to m2. i (i≥1 and are positive integers), i adjustable aggregate elements J1~J i microstrip line segment i+1 n1~n i+1 And output ports. The microstrip ring resonator is composed of a ring-shaped microstrip line; adjustable lumped elements are connected across each microstrip ring resonator, the number of microstrip ring resonators corresponding to the number of adjustable lumped elements, with one adjustable lumped element connected across each end of each microstrip ring resonator. Furthermore, the microstrip ring resonators are connected via microstrip lines, with two microstrip ring resonators at each end (microstrip ring resonator m1, microstrip ring resonator m...). i The microstrip lines n1 and n2 are connected to the input and output ports respectively. Specifically, the input port is connected to the input port of microstrip line n1. i+1 The output port is connected to the output port.

[0039] In this example, i adjustable lumped elements and microstrip ring resonators m1 to m iCoupling enables circuit equalization in at least i frequency bands, and the operating frequency, operating bandwidth, and amplitude equalization amount of i frequency bands are adjustable, which is of great benefit to the multi-functional integrated design and reconfigurable design of equipment; in addition, the entire circuit structure is simple and can adapt to the needs of miniaturized and lightweight equipment.

[0040] In one example, the adjustable lumped element is any one or more of an adjustable resistor, an adjustable inductor, and an adjustable capacitor. The impedance of the adjustable lumped element is adjusted by adjusting the resistance value and / or the inductance value and / or the capacitance value. Preferably, the adjustable lumped element is a combination of an adjustable resistor, an adjustable inductor, and an adjustable capacitor, in which case the adjustable resistor, adjustable inductor, and adjustable capacitor are connected in parallel.

[0041] In one example, the adjustable resistor R1 has a resistance range of 0 Ohm to 1000 Ohm; the adjustable capacitor C1 has a capacitance range of 0.5pF to 100pF.

[0042] In one example, the impedance adjustment method of the tuning element is any one or more of electrical adjustment, mechanical adjustment, and magnetic field adjustment.

[0043] In one example, the input port, output port, and microstrip line all have the same impedance, preferably 50 Ohms, to achieve impedance matching.

[0044] Combining the above examples yields a preferred embodiment of the present invention. In this embodiment, the broadband equalization circuit includes one or more microstrip ring resonators. Taking an equalization circuit composed of two microstrip ring resonators and an adjustable lumped element as an example, the broadband equalization circuit includes: input port 1, a first microstrip line 2, a first adjustable lumped element 3, a second microstrip line 4, a first microstrip ring resonator 5, a second adjustable lumped element 6, a second microstrip ring resonator 7, a third microstrip line 8, and an output port 9. Input port 1 is connected to the input port of the first microstrip line 2, and the two microstrip ring resonators are connected via three microstrip lines. The two adjustable lumped elements are respectively connected across the two microstrip ring resonators. The output port of the third microstrip line 8 is connected to the output port 9. The impedances of input port 1, output port 9, and the microstrip lines are all the same, all 50 ohms. The first adjustable lumped element 3 consists of an inductor L1, a resistor R1, and a capacitor C1 connected in parallel. The second adjustable lumped element 6 consists of an inductor L2, a resistor R2, and a capacitor C2 connected in parallel, and the inductance, resistance, and capacitance values ​​are adjustable. Through coupling the first adjustable lumped element 3 and the second adjustable lumped element 6 with the first microstrip ring resonator 5 and the second microstrip ring resonator 7 respectively, this circuit can achieve circuit equalization in at least two frequency bands, and the operating frequency, operating bandwidth, and amplitude equalization amount of the two frequency bands are adjustable. The specific circuit working principle is as follows:

[0045] Let the transfer matrix (ABCD matrix) of the first microstrip ring resonator 5 and the second microstrip ring resonator 8 be:

[0046]

[0047] The ABCD matrix has no explicit physical meaning and is only used to illustrate the cascading relationship of two-port networks.

[0048] Furthermore, the first microstrip ring resonator 5 and the second microstrip ring resonator 8 are connected in series in the circuit, and their transmission matrix can be simplified as follows:

[0049]

[0050] Wherein, Z1 and Z2 are the complex impedances of the first microstrip ring resonator 5 and the second microstrip ring resonator 8.

[0051] Therefore, the transmission matrix of the circuit is:

[0052]

[0053] Correspondingly, the insertion loss S of the circuit 21 for:

[0054]

[0055] Where Z0 is the characteristic impedance of the transmission line.

[0056] Correspondingly, the insertion loss S 21 The amplitude can be expressed as:

[0057]

[0058] When a microstrip ring resonator is equivalent to an RLC parallel circuit, the complex impedances Z1 and Z2 can be expressed as:

[0059]

[0060]

[0061] Where R a L a C a These represent the equivalent resistance, equivalent inductance, and equivalent capacitance of the RLC parallel circuit of the first microstrip ring resonator 5, respectively; R b L b C b These are the equivalent resistance, equivalent inductance, and equivalent capacitance of the RLC parallel circuit of the second microstrip ring resonator 8, respectively; ω is the angular frequency, and j is the imaginary unit.

[0062] When the first microstrip ring resonator 5 and the second microstrip ring resonator 8 resonate at frequencies ω1 and ω2, the magnitudes of the complex impedances Z1 and Z2 are at their maximum values.

[0063] |Z1|=R a

[0064] |Z2|=R b

[0065] Accordingly, the insertion loss S 21 amplitude | S 21 The circuit exhibits minimum values ​​at frequencies ω1 and ω2, thus enabling amplitude equalization across at least two frequency bands. This invention alters the impedance of the microstrip ring resonator by changing the values ​​of the adjustable lumped element connected across it, thereby changing the resonant frequency and consequently the insertion loss S of the circuit. 21 amplitude | S 21 This allows for the adjustment of the circuit's operating frequency, operating bandwidth, and amplitude equalization.

[0066] To further illustrate the circuit performance of the present invention, the preferred example circuit model was simulated using electromagnetic simulation software, resulting in a simulation diagram of the equalization circuit performance. Among them, Figure 3 for Figure 2 The circuit model demonstrates insertion loss performance by adjusting capacitor C1. When capacitor C1 is 2pF, the circuit exhibits amplitude equalization characteristics in both frequency bands. The center frequencies of the low-frequency and high-frequency bands are 2.7GHz and 4.3GHz, respectively, with maximum equalization values ​​of -1.1dB and -1.6dB at 2.7GHz and 4.3GHz, respectively. When capacitor C1 is 4pF, the equalization frequency band changes, with maximum equalization values ​​of -1dB and -1.3dB at 1.9GHz and 3GHz, respectively. When capacitor C1 is 6pF, the maximum equalization values ​​are -0.9dB and -1.2dB at 1.5GHz and 2.5GHz, respectively. When capacitor C1 changes from 2pF to 6pF, the circuit's operating bandwidth (the band from the insertion loss extremum to the flattening insertion loss) changes from 1GHz to 600MHz in the low-frequency band and from 2GHz to 1GHz in the high-frequency band. In summary, the circuit features adjustable operating frequency, operating bandwidth, and equalization value.

[0067] Figure 4 for Figure 2 The circuit model shows the return loss performance obtained by adjusting capacitor C1. When capacitor C1 is changed from 2pF to 6pF, the circuit's return loss is better than -11dB in the DC to 8GHz range, demonstrating good broadband performance.

[0068] Figure 5 for Figure 2The insertion loss performance of the circuit model is obtained by adjusting resistor R1. When resistor R1 is changed from 5 Ohms to 100 Ohms, the maximum equalization amount at 4.3 GHz changes from -1.5 dB to -1.7 dB, and at 2.7 GHz, it changes from -0.3 dB to -1.1 dB. Therefore, the circuit has the characteristic of adjustable equalization amount.

[0069] Figure 6 for Figure 2 The return loss performance of the circuit model is obtained by adjusting the resistor R1. When the resistor R1 is changed from 5 Ohm to 100 Ohm, the return loss of the circuit is better than -10dB in the DC to 8GHz range, showing good broadband performance.

[0070] Figures 3-6 This specific embodiment demonstrates good return loss performance and adjustable equalization characteristics over a wide operating frequency band without the need for input / output matching circuits, showcasing the advantage of simple structure.

[0071] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements, characterized in that: It includes: i microstrip ring resonators, and tunable lumped elements connected across each microstrip ring resonator, where i ≥ 1 and is a positive integer; Each microstrip ring resonator is connected to the other via a microstrip line, and the two microstrip ring resonators at the beginning and end are respectively connected to the input port and the output port via microstrip lines. The adjustable lumped element is any one or more of the following: adjustable resistor, adjustable inductor, and adjustable capacitor; The adjustable lumped element is an adjustable resistor, an adjustable inductor, and an adjustable capacitor connected in parallel; When the circuit includes two microstrip ring resonators, the transmission matrix of the circuit is: ； Where Z1 and Z2 are the complex impedances of the two microstrip ring resonators, respectively; , , , This is the transmission matrix of the circuit; , , , This is the transmission matrix of the first microstrip ring resonator; , , , This is the transmission matrix of the second microstrip ring resonator; The insertion loss S of the circuit 21 for: ； Where Z0 is the characteristic impedance of the transmission line; The insertion loss S 21 The amplitude is: ； When a microstrip ring resonator is equivalent to an RLC parallel circuit, the complex impedances Z1 and Z2 are expressed as: ； ； in These are the equivalent resistance, equivalent inductance, and equivalent capacitance of the RLC parallel circuit of the first microstrip ring resonator, respectively. These are the equivalent resistance, equivalent inductance, and equivalent capacitance of the RLC parallel circuit of the second microstrip ring resonator, respectively. Angular frequency, The imaginary unit; The first microstrip ring resonator and the second microstrip ring resonator are at the frequency , When resonance occurs, the magnitudes of the complex impedances Z1 and Z2 are at their maximum values: ； ； The two microstrip ring resonators are respectively at the frequency , When resonance occurs, the insertion loss S 21 The amplitudes at different frequencies , There exists a minimum value, thus achieving amplitude equalization in at least two frequency bands.

2. The broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements according to claim 1, characterized in that: The adjustable resistor has a resistance range of 0 Ohm to 1000 Ohm; the adjustable capacitor has a capacitance range of 0.5pF to 100pF.

3. The broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements according to claim 1, characterized in that: The impedance adjustment method of the adjustable lumped element is any one or more of electrical adjustment, mechanical adjustment, and magnetic field adjustment.

4. The broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements according to claim 1, characterized in that: The input port, output port, and microstrip line all have the same impedance.

5. The broadband equalization circuit based on a microstrip ring resonator and tunable lumped elements according to claim 4, characterized in that: The impedance of the input port, output port, and microstrip line is all 50 Ohm.

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