JP2008017159A - Transmission line type/lumped constant wilkinson divider having two kinds of phase shifters - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the reduction in the number of elements of a lumped constant 180° Wilkinson divider causing the phase difference of 180° between the two output signals which are formed by distributing high frequency wave, microwave and millimeter wave signals in two directions in the Wilkinson divider. <P>SOLUTION: In the 3 dB Wilkinson divider of two-direction transmission line type having two kinds of transmission-line type phase shifters, it is made possible to reduce the number of its elements without degrading the characteristics of the Wilkinson divider consisting of 11 elements by making the composition of the phase shifters into two equivalent π-type circuits. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a bidirectional transmission line type 3 dB Wilkinson divider having two types of transmission line type phase shifters.

A well-known circuit that distributes high-frequency, microwave, and millimeter-wave signals in two directions and gives a phase difference of 180 degrees between the two output signals is a rat race circuit that is a type of distributed constant circuit. is there. Since this circuit uses three transmission lines having a length of 1/4 of a wavelength and one transmission line having a length of 3/4 of a wavelength as constituent elements, the circuit size becomes large. One solution is to incorporate a lumped element such as a capacitor or inductor as a component. Thereby, the circuit occupation area on the substrate can be remarkably reduced from 1 / 100,000 to 1 / 1,000,000. In this case, the number of capacitors and inductors used is 10 in the rat race basic circuit (FIG. 7). As shown in FIG. 7, the lumped-constant rat race circuit has four input / output terminals and is planarly formed on the substrate. When an input is input to the terminal 1 in FIG. Further, when the signal is input from the terminal 2, the output from the terminals 3 and 1 is obtained. Normally, the communication circuit system is configured so that a signal flows from one to the other, and therefore, a part of the lumped constant rat race shown in FIG. 7 appears on the input side. For example, when an input is input to the terminal 1 in FIG. 7, it is often necessary to bring the output from the terminal 4 to the terminal 3 side by wiring. Under such circumstances, it is conceivable to give a 180 degree phase difference to the two output terminals of the Wilkinson divider. A divider has been proposed (FIG. 8) (Non-Patent Document 1). If a high frequency signal is input to the terminal 1 of this circuit, it is output from the terminals 2 and 3, and a phase difference of 180 degrees is produced between the two outputs, which is convenient. However, this circuit is composed of 11 lumped constant elements.

H.S.Nagi, Miniature lumped element 180 ° Wilkinson divider, IEEE MTT-S Symp. Dig., 2003 pp.55-58

In mobile phones and the like, functions are becoming increasingly sophisticated, and circuit sizes are being reduced by making use of microfabrication technology. By reducing the number of components as means for reducing the circuit size, it is possible to reduce the area occupied by the circuit and reduce the component cost.
The lumped-constant 180 degree Wilkinson divider of FIG. 8 uses a combination of an equivalent π-type circuit and an equivalent T-type circuit as the configuration of the phase shifter. By adopting two equivalent π-type circuits, the present inventors succeeded in reducing the number of elements without deteriorating the characteristics of the 11-element Wilkinson divider shown in FIG. Completed the invention.

With the bidirectional transmission line type 3 dB Wilkinson divider having the two types of transmission line type phase shifters of the present invention, the number of elements can be reduced, and the size and cost of the divider can be reduced.

FIG. 1 shows a bi-directional transmission line type Wilkinson divider of the present invention. Here, l ₀₁ and l ₀₂ represent the transmission line length of the phase shifter. Z ₀ is a reference characteristic impedance, line impedance Z ₁ is 2 ^0.5 Z ₀ , and absorption resistance R is 2Z _0, which are normalized and the following expression expressed in lower case is as follows.
z ₀ = 1, z ₁ = 2 ^0.5 , r = 2
Here the wavelengths of the design frequency and lambda _0, the line length l _01, l _02, respectively λ _0/4, and 3 [lambda] _0/4. When the difference l ₀₂ -l ₀₁ is equal to λ _0/2, the phase difference [psi _dif of the two outputs is given by ψ _dif = πf _n. Here, f _n is a normalized frequency and is defined by f _n = f / f ₀ . If adjustment is made so that ψ _dif becomes zero at the design frequency, ψ _dif can be rewritten as follows.
ψ _dif = π (f _n -1)

Figure 2 is in two-way transmission line Wilkinson divider of the present invention, it is a circuit diagram that lumped if the line length of the transmission line of the line impedance Z ₁ of λ _0/4. here,
C ₁ = z ₁ , C _pa = 1 / (2-2 ^0.5 ), C ^L = C ^H = 1
l _w = z ₁ , l _pa = 2 + 2 ^0.5 , l ^L = l ^H = 1

Figure 3 is a circuit diagram in the two-way transmission line Wilkinson divider, line length of the transmission line of the line impedance Z ₁ is lumped in the case of the 3 [lambda] _0/4 of the present invention. here,
C _w = y ₁ , C ^d _pa = 1 / (2 + 2 ^0.5 ), C ^L = C ^H = 1
l ₁ = y ₁ , l ^d _pa = 2-2 ^0.5 , l ^L = l ^H = 1

FIG. 4 shows the theoretical characteristics of FIG. 2, where (a) reflection and transmission characteristics and (b) phase characteristics.
The circuit shown in FIG. 2 was manufactured using the following element values.
_{C = Y 0 c n / ω} 0, L = Z 0 l n / ω 0, R = Z 0 / g a
_{Z 0 = 50Ω, Z 0 =} Y 0 -1, ω 0 = 2πf 0, f 0: the design frequency, R = Z ₀ / g _a
Here, c _n , l _n , and g _a are element values in the circuit diagram. FIG. 5 a is a comparison between theory and experiment regarding reflection and transmission characteristics at a design frequency of 500 MHz, and FIG.

FIG. 6 shows the theoretical characteristics of FIG. 3, where (a) reflection and transmission characteristics and (b) phase characteristics.
The circuit in FIG. 3 is a dual circuit in which C and L are exchanged in FIG. 2, and an experimental result equivalent to that in FIG. 5 is expected.

The bidirectional transmission line type 3 dB Wilkinson divider of the present invention can be used as a circuit for distributing and / or synthesizing signals in an external radio wave input / output unit of a communication device such as a mobile phone or satellite communication. Further, it can be used as a signal supply circuit to an antenna or a high-frequency rectification circuit.

Bi-directional transmission line type Wilkinson divider of the present invention Lumped circuit diagram of a case where the transmission line length of the line impedance Z ₁ in the two-way transmission line Wilkinson divider is lambda _0/4 Lumped circuit diagram of a case where the transmission line length of the line impedance Z ₁ in the two-way transmission line Wilkinson divider is 3 [lambda] _0/4 Reflection and transmission characteristics and the phase characteristics of the reverse-phase Wilkinson divider line length lambda _0/4 Comparison of Experiment and line length lambda _0/4 of the reversed-phase Wilkinson divider Theory (reflection and transmission characteristics) Theory and correlation of experimental reversed phase Wilkinson divider line length λ _0/4 (phase characteristics) Reflection and transmission characteristics and the phase characteristics of the reverse-phase Wilkinson divider line length 3 [lambda] _0/4 Rat race basic circuit Conventional anti-phase Wilkinson divider with 11 elements Reflection, transmission and phase characteristics of a conventional 11-phase Wilkinson divider

Claims (2)

The same reference characteristic impedance Z ₀ as a terminal load is connected to the two transmission line type phase shifters of line lengths l ₀₁ and l ₀₂ , ports 1, 2 and 3, and the line impedance Z ₁ is 2 ^0.5 Z _0, a bidirectional transmission line Wilkinson divider absorption resistance R is expressed as 2Z _0, bidirectional transmission line, characterized in that the equivalent π type circuit to ports 2 and 3 are connected type, Lumped constant type 3 dB Wilkinson divider. The bi-directional lumped constant type 3 dB Wilkinson divider according to claim 1, wherein the number of lumped constant elements is ten.

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