A lumped power divider based on T-type equivalent circuit and its design method

Abstract

The present invention designs a lumped power divider based on a T-type equivalent circuit and a design method thereof, wherein the lumped power divider includes an input port, two output ports and two branches; the two branches are symmetrical and identical; the input ends of the two branches are connected to the input port, and the output ends of the two branches are connected to at least two output ports in a one-to-one correspondence; one of the branches includes at least a first-order electromagnetic hybrid coupling T-type equivalent circuit, a second-order T-type equivalent circuit and a third-order T-type equivalent circuit. The above design ensures that the power divider achieves good working performance in each band of ultra-wideband frequency bands, the electromagnetic hybrid coupling T-type equivalent circuit effectively expands the bandwidth, and the use of resistors and capacitors for isolation has high isolation, low insertion loss, and good input and output impedance matching performance in the working frequency band, meeting the current market demand.

Description

Technical Field

[0001] The invention relates to a lumped power divider based on a T-type equivalent circuit and a design method thereof, and belongs to the field of microwave technology research. Background Art

[0002] A power divider is a multi-port microwave network that divides the input signal power into several equal or unequal outputs in a certain ratio. And it is necessary to have sufficient isolation between the output ports to avoid mutual influence between the output ports to achieve maximum power application. It is an indispensable passive device in modern microwave integrated circuits. Conversely, it can also synthesize multiple signals into one output, which is widely used in applications such as phased array radar.

[0003] The Wilkinson power divider is the most common power divider with good performance. It is widely used in actual RF microwave communication systems. Usually, the implementation of the Wilkinson power divider can be divided into waveguide type, microstrip line type, coaxial line type, etc. The standard 3dB equal power Wilkinson power divider is generally composed of two transmission lines with an electrical length of one quarter wavelength at the working center frequency and an isolation resistor with a resistance of twice the port impedance. The characteristic impedance Z0 of the transmission line is equal to the power divider port impedance Z. times.

[0004] The existing traditional one-to-two power dividers have problems such as large area, narrow frequency band, and poor performance within the working bandwidth. Therefore, analyzing and promoting miniaturized, high-performance, and ultra-wideband power dividers is the trend of future development and a hot topic now. Summary of the invention

[0005] The purpose of the present invention is to provide a lumped power divider based on a T-type equivalent circuit and a design method thereof, so as to realize ultra-wideband, low insertion loss and high isolation of a miniaturized power divider.

[0006] In order to achieve the above object, the technical solution provided by the present invention is:

[0007] In a first aspect, the present invention provides a lumped power divider based on a T-type equivalent circuit, comprising an input port, two output ports and two branches; the two branches are symmetrical and identical;

[0008] The input ends of the two branches are connected to the input port, and the output ends of the two branches are connected to the two output ports in a one-to-one correspondence;

[0009] One of the branches at least includes a first-order electromagnetic hybrid coupling T-type equivalent circuit, a second-order T-type equivalent circuit and a third-order T-type equivalent circuit.

[0010] The effect of the above settings: The above design ensures that the power divider can achieve good working performance in the C-band, X-band, and Ku-band ultra-wideband frequency bands. The T-type equivalent circuit of electromagnetic hybrid coupling effectively expands the bandwidth. The use of resistors and capacitors for isolation has high isolation, low insertion loss, and good input and output impedance matching performance within the working frequency band, meeting the current market demand.

[0011] Further, the first-order electromagnetic hybrid coupling T-type equivalent circuit includes two inductors L1 connected in series to the input port, a capacitor C1 connected in parallel between the two inductors L1 connected in series, and a capacitor C4 connected in parallel to both sides of the two inductors L1 connected in series, and the capacitor C1 is grounded;

[0012] The second-order T-type equivalent circuit includes two inductors L2 connected in series to the inductor L1 and a capacitor C2 connected in parallel between the two inductors L2 connected in series, and the capacitor C2 is grounded;

[0013] The third-order T-type equivalent circuit includes two series-connected inductors L3 connected to the inductor L2 and a capacitor C3 connected in parallel between the two series-connected inductors L3, and the capacitor C3 is grounded; the two series-connected inductors L3 are connected to the output port.

[0014] The above settings produce the following effects: the parallel capacitor C1 in the middle of the two inductors L1 connected in series is grounded. The capacitor C4 in parallel at both ends forms a first-order electromagnetic hybrid coupling T-type equivalent circuit. The inductor L1 is connected to the inductor L2, the two inductors L2 are connected in series with the parallel capacitor C2 in the middle to form a second-order T-type equivalent circuit, and the inductor L2 is connected to the inductor L3, the two inductors L3 are connected in series with the parallel capacitor C3 in the middle to form a third-order T-type equivalent circuit, thereby reducing the area of ​​the power divider, widening the bandwidth, improving the working performance, and realizing ultra-wideband, low insertion loss, and high isolation of the miniaturized power divider.

[0015] Furthermore, a branch isolation structure is provided between the two branches.

[0016] The above settings produce the following effects: the branch isolation structure can improve the isolation of the power divider.

[0017] Furthermore, the inductors L1 and L2 of the two branches are isolated by connecting a resistor R1 and a capacitor C5 in series.

[0018] The inductors L2 and L3 of the two branches are isolated by connecting a resistor R2 and a capacitor C6 in series.

[0019] A capacitor C7 is used between the inductors L3 of the two branches to achieve isolation performance.

[0020] The effect of the above settings: The first two stages of isolation in this design use resistors and capacitors in series for isolation to make up for the failure of the original T-type equivalent circuit to achieve complete port matching and energy loss. The impedance of the capacitor increases at low frequencies, while achieving good isolation in the center frequency band within the working bandwidth, adjusting the low-frequency isolation and expanding the bandwidth.

[0021] The last stage output circuit isolation uses capacitors for isolation, which achieves high isolation and adjusts the output matching to obtain good return loss, so that both the input port and the output port have good impedance matching performance.

[0022] The input port has good impedance matching performance, and the output port has good port impedance matching performance, which can be greater than 20dB. The power divider can achieve high isolation, which can be greater than 25dB.

[0023] Furthermore, the inductor uses a high impedance line and the capacitor uses an open circuit branch.

[0024] The effect of the above settings is to make the power divider have low-pass filtering characteristics.

[0025] Furthermore, the inductance values ​​L1, L2, and L3 of the inductor L1, the inductor L2, and the inductor L3 are calculated by the following formula:

[0026] ;

[0027] ;

[0028] ;

[0029] In the formula, represents the time constant, Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table lookup method.

[0030] Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit;

[0031] Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, the electrical length values ​​of θ1 and θ2 are one-quarter of the microstrip line wavelength of the center frequency of the power divider, and the third transmission line is replaced by a third-order T-type equivalent circuit.

[0032] ω1 and ω2 are the angular frequency values ​​corresponding to the center operating frequencies of the power dividers of the second transmission line and the third transmission line respectively.

[0033] Furthermore, the capacitance values ​​C1, C2, C3, C4, C5, C6, and C7 of the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C6, and the capacitor C7 are calculated by the following formula:

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] In the formula, represents the time constant, Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table lookup method.

[0042] Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit;

[0043] Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, and the third transmission line is replaced by a third-order T-type equivalent circuit.

[0044] ω, ω1, and ω2 are angular frequency values ​​corresponding to the center operating frequencies of the power dividers of the first transmission line, the second transmission line, and the third transmission line, respectively.

[0045] Furthermore, the resistance values ​​R1 and R2 of the isolation resistor R1 and the isolation resistor R2 are calculated by the following formula:

[0046]

[0047]

[0048] In the formula, represents the time constant, Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table lookup method.

[0049] Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit; the electrical length values ​​of θ1 and θ2 are λ / 4 wavelength of the center frequency of the power divider.

[0050] Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, and the third transmission line is replaced by a third-order T-type equivalent circuit.

[0051] In a second aspect, the present invention provides a design method of a lumped power divider based on a T-type equivalent circuit as described in the first aspect, comprising the following steps:

[0052] A T-type equivalent circuit is used to replace each section of the λ / 4 microstrip line of the third-order LC lumped element.

[0053] Further, the method of using a T-type equivalent circuit to replace each section of the λ / 4 microstrip line of the third-order LC lumped element includes:

[0054] The first-order LC matching circuit of the third-order LC lumped element is designed by using the corresponding first-order electromagnetic hybrid coupled T-type equivalent circuit to replace the quarter-wavelength microstrip line;

[0055] The second-order LC matching circuit and the third-order LC matching circuit of the third-order LC lumped element use the second-order T-type equivalent circuit and the third-order T-type equivalent circuit to replace the microstrip line;

[0056] The first-order electromagnetic hybrid coupling T-type equivalent circuit includes two inductors L1 connected in series to the input port of the lumped power divider, a capacitor C1 connected in parallel between the two inductors L1 in series, and a capacitor C4 connected in parallel to both sides of the two inductors L1 in series, and the capacitor C1 is grounded;

[0057] The second-order T-type equivalent circuit includes two inductors L2 connected in series to the inductor L1 and a capacitor C2 connected in parallel between the two inductors L2 connected in series, and the capacitor C2 is grounded;

[0058] The third-order T-type equivalent circuit includes two series-connected inductors L3 connected to the inductor L2 and a capacitor C3 connected in parallel between the two series-connected inductors L3, and the capacitor C3 is grounded; the two series-connected inductors L3 are connected to the output port of the lumped power divider.

[0059] The effect of the above settings is: combining the advantages of the π-type equivalent structure and the T-type equivalent structure to better adjust the input matching, and the transmission characteristic curve is more consistent with the ideal transmission model.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The present invention ensures that the power divider achieves good working performance in the C-band, X-band, and Ku-band ultra-wideband frequency bands through the above-mentioned design. The T-type equivalent circuit of electromagnetic hybrid coupling effectively expands the bandwidth. The use of resistors and capacitors for isolation has high isolation, low insertion loss, and good input and output impedance matching performance within the working frequency band, meeting the current market demand.

[0062] The three ports of the power divider have good impedance matching performance at the center frequency, the output port has good isolation characteristics within the ultra-wideband working bandwidth, and has the characteristics of low insertion loss. The power divider achieves ultra-wideband and high performance while meeting the requirements of miniaturization, and has good development prospects.

[0063] The inductor used in the present invention adopts a high impedance line, and the capacitor adopts an open-circuit branch, which has a low-pass filtering characteristic. The circuit design uses a capacitive branch loading technology and a multi-section quarter-wavelength transmission line cascade technology to effectively improve the miniaturization and bandwidth capability of the power divider. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 The present invention is a topological design diagram of a lumped power divider based on a T-type equivalent circuit.

[0065] Figure 2 It is the layout design of the present invention in electromagnetic simulation software ADS software.

[0066] Figure 3 This is the example simulation result 1 in the electromagnetic simulation software.

[0067] Figure 4 This is the example simulation result 2 in the electromagnetic simulation software.

[0068] Figure 5 It is a schematic diagram of the structure of a basic third-order LC lumped element. DETAILED DESCRIPTION

[0069] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0070] The present invention designs an ultra-wideband one-to-two power divider topology structure suitable for C, X, and Ku bands and a design method thereof. The power divider is a fully lumped power divider composed of capacitors, inductors, and resistors. A third-order LC resonant network is connected in series to form a main circuit, and capacitors and resistors are connected in series for isolation. The three ports of the power divider have good impedance matching performance at the center frequency, and the output port has good isolation characteristics within the ultra-wideband working bandwidth and has the characteristics of low insertion loss. The power divider achieves ultra-wideband and high performance while meeting the requirements of miniaturization, and has good development prospects.

[0071] The present invention discloses a lumped power divider based on a T-type equivalent circuit, and its basic structure is as follows: Figure 1As shown, the three ports of the power divider design proposed in the present invention have good impedance matching characteristics, and the two output ports are isolated from each other (IN in the figure represents the input port, and OUT represents the output port). The circuit structure is divided into two branches by the input port, and the two branches are completely identical and symmetrical up and down. First, the two inductors L1 connected in series are connected in parallel with the capacitor C1 in the middle to ground. The capacitor C4 connected in parallel at both ends constitutes a first-order electromagnetic hybrid coupling T-type equivalent circuit. The inductor L1 is connected to the inductor L2, and the two inductors L2 are connected in series with the capacitor C2 in the middle to ground to form a second-order T-type equivalent circuit. The inductor L2 is connected to the inductor L3, and the two inductors L3 are connected in series with the capacitor C3 in the middle to ground to form a third-order T-type equivalent circuit.

[0072] The inductor L1 and the inductor L2 are isolated for the first order, and the upper and lower branches are isolated by using a resistor R1 and a capacitor C5 in series. The inductor L2 and the inductor L3 are isolated for the second order, and the upper and lower branches are isolated by using a resistor R2 and a capacitor C6 in series. The upper and lower branches of the inductor L3 are isolated for the third order, and the capacitor C7 is used to achieve isolation performance.

[0073] The design is strictly symmetrical between the upper and lower branches to achieve equal phase and power distribution to the greatest extent, reduce the interaction of the electromagnetic fields of the two branches, and avoid the deterioration of performance due to parasitic coupling effects. The input port reflected power is minimized to the greatest extent, and the output port matching voltage is kept equal and in phase.

[0074] The parameter values ​​of the design components are calculated by the following formula:

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] In the formula, The meaning of is the time constant. In such a circuit, when a constant current flows, the time required for the terminal voltage of the capacitor to reach 1-1 / e of the maximum value (equal to IR), that is, about 0.63 times, is the time constant. , and when the circuit is disconnected, the time constant is the time required for the terminal voltage of the capacitor to reach 1 / e of the maximum value.

[0088] Z0 is the characteristic impedance of the first transmission line (the value of each component of the equivalent circuit needs to be calculated based on the most basic transmission line structure), which is calculated by the power divider performance parameter lookup table method, and the value is 86.98 ohms. θ is the electrical length of the first transmission line (the three electrical lengths θ, θ1, and θ2 have the same value), and the electrical length is one-quarter of the wavelength of the center frequency (the middle value of the working frequency band of the designed power divider). The first transmission line is replaced by a first-order electromagnetic hybrid coupled T-type equivalent circuit (the performance of the first transmission line can be replaced by a first-order electromagnetic hybrid coupled T-type equivalent circuit structure to achieve the same effect). The values ​​of inductance L1, capacitance C1, capacitance C4, and capacitance C5 can be obtained by calculation.

[0089] Z1 is the characteristic impedance of the second transmission line, which is 70.71 ohms. θ1 is the electrical length of the second transmission line. The second transmission line is replaced by a second-order T-type equivalent circuit. The values ​​of inductance L2, capacitance C2, and capacitance C6 can be obtained by calculation.

[0090] Z2 is the characteristic impedance of the third transmission line, which is 50.49 ohms. θ2 is the electrical length of the third transmission line. In this formula, the values ​​of the three electrical lengths are consistent because the working center frequencies are consistent. The third transmission line is replaced by a third-order T-type equivalent circuit. The values ​​of inductance L3, capacitance C3, and capacitance C7 can be obtained by calculation.

[0091] ω, ω1, and ω2 are the angular frequency values ​​corresponding to the center operating frequencies of the power dividers of the first transmission line, the second transmission line, and the third transmission line, respectively, which are equal to 2πf and are related to the design operating frequency f of the power divider.

[0092] The input port has good impedance matching performance, and the output port has good port impedance matching performance, greater than 20dB. The power divider can achieve high isolation, greater than 25dB.

[0093] Each λ / 4 microstrip line of the power divider is replaced by a corresponding electromagnetic hybrid coupled T-type equivalent circuit structure.

[0094] The capacitive branch loading technology is adopted to connect capacitor C1 in series between two identical inductors L1 and ground them, connect capacitor C4 in parallel at both ends of two identical inductors, connect capacitor C2 in series between two identical inductors L2 and ground them, and connect capacitor C3 in series between two identical inductors L3 and ground them.

[0095] The present invention uses a multi-section quarter-wavelength transmission line cascade technology, and the first section of the λ / 4 microstrip line (quarter-wavelength microstrip line) is replaced by an electromagnetic hybrid coupled T-type equivalent circuit structure inductor L1, capacitor C1, C4. The second section of the λ / 4 microstrip line is replaced by a T-type equivalent circuit structure inductor L2 and capacitor C2. The third section of the λ / 4 microstrip line is replaced by a T-type equivalent circuit structure, inductor L3, and capacitor C3.

[0096] The inductor uses a high impedance line and the capacitor uses an open-circuit branch, which has a low-pass filtering characteristic.

[0097] Embodiment 1:

[0098] This embodiment provides a lumped power divider based on a T-type equivalent circuit, and specifically proposes a one-to-two power divider with a center frequency of 9 GHz applied to 5 GHz to 13 GHz, with an operating bandwidth of 8 GHz. The isolation part is designed to use resistors and capacitors in series for isolation, to make up for the failure of the original T-type equivalent circuit to achieve complete port matching and energy loss. The impedance of the capacitor increases at low frequencies, and the low-frequency isolation is adjusted while achieving good isolation in the center frequency band within the working bandwidth, thereby expanding the bandwidth. Capacitors are used for isolation in the last-order output circuit, and the output matching is adjusted to obtain good return loss while achieving high isolation. This ensures that both the input port and the output port have good impedance matching performance.

[0099] The present invention designs a third-order LC lumped element combined with a T-type equivalent circuit to replace each section of an original λ / 4 microstrip line (quarter wavelength microstrip line).

[0100] The first-order LC matching circuit uses the corresponding electromagnetic hybrid coupling T-type equivalent circuit structure to replace the λ / 4 microstrip line. The second and third orders use the ideal transmission line T-type equivalent circuit to replace the microstrip line, combining the advantages of the π-type equivalent structure and the T-type equivalent structure to better adjust the input matching, and the transmission characteristic curve is more consistent with the ideal transmission model.

[0101] In this design, the inductor uses a high impedance line and the capacitor uses an open-circuit branch, which has a low-pass filtering characteristic. The capacitive branch loading technology and the multi-section quarter-wavelength transmission line cascade technology can effectively expand the bandwidth.

[0102] Combination Figure 1 and Figure 3 This embodiment is verified by the simulation results of the electromagnetic simulation software ADS software, and proposes a one-to-two power divider with a center frequency of 9 GHz applied to 5 GHz to 13 GHz, and a working bandwidth of 8 GHz.

[0103] Figure 3This is the simulation result of an example of a one-to-two power splitter with a center frequency of 9 GHz and an operating bandwidth of 8 GHz in an electromagnetic simulation software.

[0104] Figure 3 In the figure, the horizontal axis is the frequency, and the vertical axis represents the simulation results of the power divider performance indicators at each frequency, and the unit is decibel (dB);

[0105] Figure 3 Among the four line segments, S (2, 2) is the output return loss, which is the reflection caused by the impedance mismatch of the output cable link, and is the reflection of a pair of lines themselves. Return loss is the ratio of the reflected wave power to the incident wave power at the transmission line port.

[0106] S(1,1) is the input return loss, which is the reflection caused by the impedance mismatch of the input cable link, and is the reflection of a pair of lines themselves. The return loss is the ratio of the reflected wave power to the incident wave power at the transmission line port.

[0107] S (2, 3) is the isolation, which is the interference suppression performance achieved in order to minimize the impact of various interferences on the receiver.

[0108] S(2,1) is the insertion loss. Insertion loss refers to the loss of load power caused by the insertion of a component or device somewhere in the transmission system. It is expressed as the ratio of the power received by the load before the component or device is inserted to the power received by the same load after the insertion in decibels.

[0109] Figure 3-4 It shows that the power divider has good performance in all aspects. The structure can not only achieve miniaturization but also realize high isolation, low insertion loss and good impedance matching within the ultra-wideband working frequency band.

[0110] Combination Figure 1 and Figure 3 This embodiment is verified by the simulation results of the electromagnetic simulation software ADS software, and it is proposed to use a one-to-two power divider with a center frequency of 9 GHz as the indicator for 5 GHz to 13 GHz, and the working bandwidth is 8 GHz. Through the calculation of the component parameters of the present invention, the simulation circuit chip is miniaturized to 2.2mm*1.5mm. Within the ultra-wideband working bandwidth, S (2, 3) shows an isolation greater than 27dB, S (1, 1) shows an input return loss greater than 20dB, S (2, 2) shows an output return loss greater than 20dB, and S (2, 1) shows an insertion loss of about 1dB within the working frequency band. Good performance is achieved in the ultra-wideband operation. The example layout design is as follows Figure 2 The simulation results are shown in Figure 3 shown.

[0111] Figure 3It shows that the power divider has good performance in all aspects. The structure can not only achieve miniaturization but also realize high isolation, low insertion loss and good impedance matching within the ultra-wideband working frequency band.

[0112] Embodiment 2:

[0113] This embodiment provides a lumped power divider based on a T-type equivalent circuit, and specifically proposes a one-to-two power divider applied to 6 GHz to 18 GHz with a center frequency of 12 GHz as an indicator, and a working bandwidth of 12 GHz.

[0114] Combination Figure 1 and Figure 4 This embodiment is verified by the simulation results of the electromagnetic simulation software ADS software, and proposes a one-to-two power divider with a center frequency of 12 GHz as an indicator for application in the range of 6 GHz to 18 GHz, and a working bandwidth of 12 GHz.

[0115] Figure 4 This is the simulation result of an example of a one-to-two power divider with a working bandwidth of 12 GHz in an electromagnetic simulation software with a center frequency of 12 GHz applied to 6 GHz to 18 GHz.

[0116] Figure 4 In the figure, the horizontal axis is the frequency, and the vertical axis represents the simulation results of the power divider performance indicators at each frequency, and the unit is decibel (dB);

[0117] Figure 4 Among the four line segments, S (2, 2) is the output return loss, which is the reflection caused by the impedance mismatch of the output cable link, and is the reflection of a pair of lines themselves. Return loss is the ratio of the reflected wave power to the incident wave power at the transmission line port.

[0118] S(1,1) is the input return loss, which is the reflection caused by the impedance mismatch of the input cable link, and is the reflection of a pair of lines themselves. The return loss is the ratio of the reflected wave power to the incident wave power at the transmission line port.

[0119] S (2, 3) is the isolation, which is the interference suppression performance achieved in order to minimize the impact of various interferences on the receiver.

[0120] S(2,1) is the insertion loss. Insertion loss refers to the loss of load power caused by the insertion of a component or device somewhere in the transmission system. It is expressed as the ratio of the power received by the load before the component or device is inserted to the power received by the same load after the insertion in decibels.

[0121] Figure 3-4 It shows that the power divider has good performance in all aspects. The structure can not only achieve miniaturization but also realize high isolation, low insertion loss and good impedance matching within the ultra-wideband working frequency band.

[0122] Combination Figure 1 and Figure 4 This embodiment is verified by the simulation results of the electromagnetic simulation software ADS software, and it is proposed to use a one-to-two power divider with a center frequency of 12 GHz as the indicator for 6 GHz to 18 GHz, and the working bandwidth is 12 GHz. Through the calculation of component parameters described in this design, the simulation circuit chip is miniaturized to 2.1mm*1.3mm. Within the ultra-wideband working bandwidth, S (2, 3) shows an isolation greater than 23dB, S (1, 1) shows an input return loss greater than 18dB, S (2, 2) shows an output return loss greater than 20dB, and S (2, 1) shows an insertion loss of about 1dB within the working frequency band. Good performance is achieved in the ultra-wideband operation. The example layout design is as follows Figure 2 The simulation results are shown in Figure 4 shown.

[0123] Embodiment three:

[0124] This embodiment provides a design method of a lumped power divider based on a T-type equivalent circuit as described in Embodiment 1, comprising the following steps:

[0125] Use a T-type equivalent circuit to replace each section of the λ / 4 microstrip line (quarter-wavelength microstrip line) of the third-order LC lumped element. Common third-order LC lumped elements include Figure 5 shown.

[0126] Methods for using a T-type equivalent circuit to replace each section of the λ / 4 microstrip line of the third-order LC lumped element include:

[0127] The first-order LC matching circuit of the third-order LC lumped element is designed by using the corresponding first-order electromagnetic hybrid coupled T-type equivalent circuit to replace the λ / 4 microstrip line;

[0128] The second-order LC matching circuit and the third-order LC matching circuit of the third-order LC lumped element use the second-order T-type equivalent circuit and the third-order T-type equivalent circuit to replace the microstrip line;

[0129] The first-order electromagnetic hybrid coupling T-type equivalent circuit includes two inductors L1 connected in series to the input port of the lumped power divider, a capacitor C1 connected in parallel between the two inductors L1 in series, and a capacitor C4 connected in parallel to both sides of the two inductors L1 in series, and the capacitor C1 is grounded;

[0130] The second-order T-type equivalent circuit includes two inductors L2 connected in series to the inductor L1 and a capacitor C2 connected in parallel between the two inductors L2 connected in series, and the capacitor C2 is grounded;

[0131] The third-order T-type equivalent circuit includes two series-connected inductors L3 connected to the inductor L2 and a capacitor C3 connected in parallel between the two series-connected inductors L3, and the capacitor C3 is grounded; the two series-connected inductors L3 are connected to the output port of the lumped power divider.

[0132] The design method of this embodiment combines the advantages of the π-type equivalent structure and the T-type equivalent structure to better adjust the input matching, and the transmission characteristic curve is more consistent with the ideal transmission model.

[0133] The inductor used in the present invention adopts a high impedance line, and the capacitor adopts an open-circuit branch, which has a low-pass filtering characteristic. The circuit design uses a capacitive branch loading technology and a multi-section quarter-wavelength transmission line cascade technology to effectively improve the miniaturization and bandwidth capability of the power divider.

[0134] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features, and in the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0135] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0136] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0137] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0138] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A lumped power divider based on a T-type equivalent circuit, characterized in that: It includes an input port, two output ports and two branches; the two branches are symmetrical and identical; The input ends of the two branches are connected to the input port, and the output ends of the two branches are connected to the two output ports in a one-to-one correspondence; The branch circuit includes a first-order electromagnetic hybrid coupled T-type equivalent circuit, a second-order T-type equivalent circuit and a third-order T-type equivalent circuit; The first-order electromagnetic hybrid coupling T-type equivalent circuit includes two inductors L1 connected in series to the input port, a capacitor C1 connected in parallel between the two inductors L1 connected in series, and a capacitor C4 connected in parallel to both ends of the two inductors L1 connected in series, and the capacitor C1 is grounded; The second-order T-type equivalent circuit includes two inductors L2 connected in series to the inductor L1 and a capacitor C2 connected in parallel between the two inductors L2 connected in series, and the capacitor C2 is grounded; The third-order T-type equivalent circuit includes two series-connected inductors L3 connected to the inductor L2 and a capacitor C3 connected in parallel between the two series-connected inductors L3, and the capacitor C3 is grounded; the two series-connected inductors L3 are connected to the output port.

2. The lumped power divider based on a T-type equivalent circuit according to claim 1, characterized in that: A branch isolation structure is provided between the two branches; The two branches are isolated by connecting a resistor R1 and a capacitor C5 in series between the inductor L1 and the inductor L2. The two branches are isolated by connecting a resistor R2 and a capacitor C6 in series between the inductor L2 and the inductor L3. The two branches use a capacitor C7 between the inductor L3 and the output port to achieve isolation performance.

3. The lumped power divider based on a T-type equivalent circuit according to claim 2, characterized in that: All inductors use high impedance wires and all capacitors use open-circuit stubs.

4. The lumped power divider based on a T-type equivalent circuit according to claim 2, characterized in that: The inductance values ​​L1, L2, L3 of the inductor L1, the inductor L2, and the inductor L3 are calculated by the following formula: ； ； ； In the formula, represents the time constant, Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table method. Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit; Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, and the third transmission line is replaced by a third-order T-type equivalent circuit. ω1 and ω2 are the angular frequency values ​​corresponding to the center operating frequencies of the power dividers of the second transmission line and the third transmission line respectively.

5. The lumped power divider based on a T-type equivalent circuit according to claim 4, characterized in that: The capacitance values ​​C1, C2, C3, C4, C5, C6, and C7 of the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C6, and the capacitor C7 are calculated by the following formula: ； ； ； ； ； ； ； In the formula, represents the time constant, Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table method. Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit; Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, and the third transmission line is replaced by a third-order T-type equivalent circuit. ω, ω1, and ω2 are angular frequency values ​​corresponding to the center operating frequencies of the power dividers of the first transmission line, the second transmission line, and the third transmission line, respectively.

6. The lumped power divider based on a T-type equivalent circuit according to claim 4, characterized in that: The resistance values ​​R1 and R2 of the resistor R1 and the resistor R2 are calculated by the following formula: ； ； Where Z0 is the characteristic impedance of the first transmission line, which is calculated by the power divider performance parameter table lookup method. Z1 is the characteristic impedance of the second transmission line, θ1 is the electrical length of the second transmission line, and the second transmission line is replaced by a second-order T-type equivalent circuit; Z2 is the characteristic impedance of the third transmission line, θ2 is the electrical length of the third transmission line, and the third transmission line is replaced by a third-order T-type equivalent circuit.

7. A design method for a lumped power divider based on a T-type equivalent circuit as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Each quarter-wavelength microstrip line section is replaced by a T-type equivalent circuit of a third-order LC lumped element; Methods for using a T-type equivalent circuit to replace each quarter-wavelength microstrip line section of a third-order LC lumped element include: The first-order LC matching circuit of the third-order LC lumped element adopts the corresponding first-order electromagnetic hybrid coupled T-type equivalent circuit to replace the quarter-wavelength microstrip line; The second-order LC matching circuit and the third-order LC matching circuit of the third-order LC lumped element use the second-order T-type equivalent circuit and the third-order T-type equivalent circuit to replace the microstrip line; The first-order electromagnetic hybrid coupling T-type equivalent circuit includes two inductors L1 connected in series to the input port of the lumped power divider, a capacitor C1 connected in parallel between the two inductors L1 in series, and a capacitor C4 connected in parallel to both sides of the two inductors L1 in series, and the capacitor C1 is grounded; The second-order T-type equivalent circuit includes two inductors L2 connected in series to the inductor L1 and a capacitor C2 connected in parallel between the two inductors L2 connected in series, and the capacitor C2 is grounded; The third-order T-type equivalent circuit includes two series-connected inductors L3 connected to the inductor L2 and a capacitor C3 connected in parallel between the two series-connected inductors L3, and the capacitor C3 is grounded; the two series-connected inductors L3 are connected to the output port of the lumped power divider.

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