RU2655038C1 - Power divider - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to microwave engineering and can be widely used in active phased antenna array systems, radio transmitting devices and systems using microwave power. Proposed is a power divider comprising an input arm connected via quarter-wave transmission line segments to output arms, between which there are ballast resistors, made in the form of transmission line segments with losses and connected in star, common point of which is connected to a short-circuited loop conductor with the length less than a quarter wavelength of the central frequency of the operating range, input arm is connected to an additional capacitance, selected from ratio

where ω₀=2πƒ₀, ƒ₀ – central frequency of the operating range, R=R₀=R_n – standard value of the input and output impedances of the power divider, n is the number of output arms (channels) of the power divider, Z_ine=Z_R(Z_inl+Z_RthθR)/(Z_R+Z_inlthθ_R) – input resistance of the branch of the power divider arm composed of a series-connected ballast resistor in the form of a transmission line segment with losses with parameters Z_R, l_R, θ_R=2πl_R/λ₀ and a short-circuited corrective loop with an input resistance Z_inl=inρ_shtgθsh=iX, θsh=2πl_sh/λ₀, whence lsh=(λ₀/2π)arctg(X/nρ_sh), λ₀ – wavelength in the power divider.

EFFECT: technical result is improved decoupling between output arms of the power divider and higher forward transfer constant.

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Description

The invention relates to microwave technology and can be widely used in systems of active phased array antennas, radio transmitting devices and systems using microwave power.

A known power divider containing a splitter of quarter-wave segments of transmission lines to the outputs of which are connected ballast decoupling resistors connected by a star (Wilkinson EJ An N-hybrid power divider // IRE Trans. On microwave theory and techniques. 1960. v. MTT-8, N 1.p. 116-118). Over the past more than 50 years, this device has been repeatedly improved and formed the basis of a large number of copyright certificates and patents. Being linear and reciprocal, the Wilkinson divider can equally be used as a power adder.

A known power divider (see. Power addition device, ed. Certificate of the USSR No. 1170534, НРР 5/12, BI No. 28. 07.30.85), containing input arms, each of which is connected to a ballast resistor and a quarter-wave length of the transmission line, with In this case, the ballast resistors are connected to a star, the ends of the quarter-wave segments of the transmission lines are connected to the output arm, and a short-circuited quarter-wave loop is connected to the common point of the ballast resistors. The suppression of the even harmonics of the summed generators is successfully performed at the center frequency of the range for which the input impedance of the quarter-wave loop is infinitely large and, therefore, this loop does not affect the operation of the device. In this case, the even harmonics of the summed generators are shorted to ground, since for them the length of the loop is not a quarter, but a half-wave, or a multiple of it, and the input impedance of such a loop is zero.

When operating at a high power level, the area of the ballast resistors in the film version and, as a result, their parasitic parameters increase, which leads to a sharp deterioration in the technical characteristics of the device - matching at the inputs, decoupling between them, reducing the direct transfer coefficient, increasing losses in the ballast resistors, frequency displacement of the VSWR minima and the isolation maximum, etc.

A power divider is also known (see ed. Certificate of the USSR No. 849342, НРР 5/12, БИ No. 27. 07.25.81), comprising a splitter, to the output arms of which decoupling resistors connected by a star are connected; short-circuited loops are connected to the input and to each of the outputs of the splitter arms, and a capacitor is connected to each splitter arm, and the capacitor capacitance and the length of each of the short-circuited loops are determined respectively from the relations

where n is the number of shoulders;

ƒ ₀ is the central frequency of the operating range;

R ₀ is the output impedance of each arm of the divider;

λ ₀ is the wavelength in the power divider;

ρ - wave impedance of a short-circuited loop.

Reducing losses and reducing the dimensions of the device is achieved by equivalent replacing the quarter-wave transforming segments of the splitter transmission line with U-shaped semi-distributed links composed of two short-circuited loops in parallel branches and a concentrated capacitance in the serial branch of each P-link. However, the choice of P-link elements according to the above ratios does not allow to compensate for the deterioration of the technical characteristics of a high-power device with an increased area of ballast resistors in a film version. As in the previous case, the achievement of high values of the above technical characteristics cannot be implemented in this device.

In addition, a power divider is known (see ed. Certificate of the USSR No. 1798840, Н01Р 5/12, BI No. 8. 02.28.93), which is a prototype of the invention and contains an input arm connected through quarter-wave segments of the transmission line to the output arms, at the same time, ballast resistors connected to the star and connected to a common point with a short-circuited loop are connected between the output arms, while the ballast resistors are made in the form of segments of the transmission line with losses, the loop length is selected less than a quarter of the wavelength of the center frequency of the working th band, and its input impedance is selected from the relations:

where Z _C , L is the impedance and the length of the length of the transmission line with losses;

γ is the propagation constant in the lossy line;

- волновое сопротивление и длина шлейфа.Z _W

- wave impedance and loop length.

In the prototype, an increase in operating power is achieved by connecting a short-circuit loop connected to a common point of ballast resistors with a length of less than a quarter of the wavelength of the center frequency of the operating range. This loop compensates for the parasitic parameters of ballast resistors and improves the matching of inputs and outputs, isolation between the outputs, increases the direct transmission coefficient and, as a result, the operating power at the outputs.

However, despite a significant improvement in the indicated technical characteristics, their values are not high enough, which primarily concerns the isolation between the outputs of the divider, that is, ensuring their independent operation under various loading and operating conditions, and the direct transmission coefficient.

The objective (technical result) of the present invention is to improve the isolation between the output arms of the power divider and increase the coefficient of its direct transmission.

This object is achieved by the fact that in the power divider containing the input arm connected through quarter-wave segments of the transmission line to the output arms, between which are included ballast resistors connected in the star, made in the form of segments of the transmission line with losses, and to the common point of which a short-circuited loop is connected , the length of which is less than a quarter of the wavelength of the central frequency of the operating range, a capacitance connected to its input arm and selected from the relation

where ω ₀ = 2πƒ ₀ , ƒ ₀ is the central frequency of the working range,

R = R ₀ = R _n - the standard value of the input and output resistances of the power divider,

n is the number of output arms (channels) of the power divider,

- входное сопротивление ветви плеча делителя мощности, составленной из последовательно соединенных балластного резистора в виде отрезка линии передачи с потерями с параметрами Z_R,

,

и короткозамкнутого корректирующего шлейфа с входным сопротивлением Z _вхш =inρ _ш tgθ _ш =iX,

, откуда

,

- input resistance of the arm branch of the power divider, composed of series-connected ballast resistor in the form of a segment of the transmission line with losses with parameters Z _R ,

,

and a short-circuited correction loop with input impedance Z _vhsh = inρ _w tgθ _w = iX ,

from where

,

λ ₀ - wavelength in the power divider.

The initial formulas, equivalent circuits of the arm of the power divider, design relationships and notation are given in the works of K. Ya. Aubakirov, V.I. Govorukhin, L.G. Plavsky, M.G. Rubanovich Two-channel common-mode adder-power divider with compensation of parasitic parameters of the ballast resistor. Radio engineering, No. 6, 2011, p. 59-63 and V.I. Govorukhin, M.G. Rubanovich, N.E. Unruh Wilkinson multi-channel common-mode combiners-dividers with compensation of spurious parameters of ballast resistors. Questions of Radio Electronics, General Technical Series, vol. 3, p. 102-114.

In FIG. 1 is a schematic electrical diagram of the proposed n- channel power divider, FIG. 2 is a schematic electrical diagram of the proposed two-channel power divider, FIG. 3 - frequency dependence of the technical characteristics of the proposed two-channel power divider.

The power divider (Fig. 1) contains an input arm 1 with a connected capacitance 2 connected through quarter-wave segments of the transmission line 3 to the output arms 4, each of which is connected with a ballast resistor 5, made in the form of a segment of a transmission line with losses, all ballast resistors are connected a short-circuited loop 6 with a length less than a quarter of the wavelength of the center frequency of the operating range is connected to the star and to their common point. The output arms 4 of the divider are loaded on the load resistance 7.

The power divider (Fig. 1) works as follows. When the input microwave signal arrives at the input arm 1, its power is evenly distributed through the same quarter-wave segments of the transmission line 3 to all output arms 4, so that with the same and coordinated load resistances 7, these powers on all output arms 4 are equal in phase and in phase. For the case of a minimum area of ballast resistors, the power divider is a symmetrical multipole and at the center frequency it is completely matched, and its outputs are decoupled almost perfectly. In high power devices, it is necessary to use ballast resistors with a large area to dissipate significant power in the event of a mismatch or failure of one of the loads. The technical characteristics of such power dividers are significantly degraded, and therefore, to ensure their operability, it is necessary to adjust the effect of the effect associated with the use of ballast resistors with a large area. This is partially implemented in the prototype device by connecting to the common point of the short-circuit loop 6 included in the star of the ballast resistors 6. In the proposed device, an additional capacitance 2 is connected to the input arm of the power divider (Fig. 1), which improves the isolation between the output arms and increases the coefficient its direct transmission.

The results of the study of a two-channel power divider - prototype are given in the article by K.Ya. Aubakirov, V.I. Govorukhin, L.G. Plavsky, M.G. Rubanovich. Two-channel common-mode adder-power divider with compensation of parasitic parameters of the ballast resistor. - Radio engineering, No. 6, 2011, p. 59-63. Frequency dependences of the technical characteristics of the proposed two-channel power divider (FIG. 2) are presented in FIG. 3. A comparison of these characteristics shows that the introduction of a small additional capacitance With _additional = 0.59 pF , connected to the input arm of the power divider (Fig. 2), provides:

- the parameter ⎜ S _ik ⎜ = -58.74 dB, characterizing the isolation between the output arms of the device, increased by 24 dB compared with the power divider - the prototype and almost corresponds to the divider with a non-reactive ballast resistor;

- coefficients of a standing voltage wave: at the input KCBH ₁ = 1.104 at a frequency of 961 MHz, at the output of the VSWR ₄ = 1.036 at a frequency of 826 MHz are close to the corresponding values for the prototype power divider;

- the direct transmission coefficient ⎜ S ₄₁ ⎜ = -3.139 dB increased by 3.5% compared with the power divider prototype.

Thus, the introduction of a capacitance connected to the input arm of the power divider significantly improved the isolation between its output arms and increased the direct transmission coefficient.

Claims (6)

A power divider comprising an input arm connected via quarter-wave segments of the transmission line to output arms, between which are included ballast resistors made in the form of segments of the transmission line with losses and connected to a star, to the common point of which there is a short-circuited loop less than a quarter of the wavelength of the central frequency operating range, characterized in that a capacitance connected to its input arm and selected from the ratio

, where ω ₀ = 2πƒ ₀ , ƒ ₀ is the central frequency of the working range, R = R ₀ = R _n - the standard value of the input and output resistances of the power divider, n is the number of output arms (channels) of the power divider,

- input resistance of the arm branch of the power divider, composed of series-connected ballast resistor in the form of a segment of the transmission line with losses with parameters Z _R ,

,

and a short-circuited correction loop with input impedance Z _vhsh = inρ _w tgθ _w = iX,

from where

, λ ₀ is the wavelength in the power divider.

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