JPH0756929B2 - Hybrid circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hybrid circuit that divides an input signal into two so that the phase difference between output signals becomes a predetermined phase difference.

[Prior Art] FIG. 4 is a circuit diagram of a conventional 90-degree hybrid circuit (Hideho Yamamura, "Encyclopedia of Toroidal Core Utilization," 1983 1
Mon, CQ Publishing, pp366, see Figures 6-39).

In this conventional 90-degree hybrid circuit, for example, a bifilar winding that forms two inductors L1 and L2 is wound around a toroidal core, and a capacitor C1 is connected between each end of the inductors L1 and L2. A capacitor C2 is connected between the other ends of L2. Here, both ends of the inductor L1 are ports P1 and P2, both ends of the inductor L2 are ports P3 and P4, and ports P2 and P3 are
Is grounded through terminating resistors R _L2 and R _L1 , respectively, and port P4 is terminating resistor equal to characteristic impedance Z _0.
Grounded via R _L.

In the conventional 90-degree hybrid circuit configured as described above, when a high-frequency signal having a reference phase of 0 degrees is input to the port P1 from the high-frequency signal oscillator 10 having an output resistance R _S equal to the characteristic impedance Z ₀ , the high-frequency signal is changed. The signal is divided into two, and a signal having a phase of −45 degrees and a signal having a phase of +45 degrees are output to the ports P2 and P3, respectively, while no signal is output to the port P4. That is, the phase difference between the signals output to the ports P2 and P3 is 90 degrees and the amplitude levels of the signals are the same.

[Problems to be Solved by the Invention] FIG. 6 shows the frequency characteristics of the phase difference between the forward transfer coefficients S ₂₁ , S ₃₁ and the signals output to the ports P2 and P3 of the conventional 90-degree hybrid circuit described above. Show.

As is clear from FIG. 6, the phase difference between the signals output to the ports P2 and P3 is 90 degrees at a frequency of about 140 MHz, but about 94 degrees at 100 MHz and about 200 degrees at 200 MHz.
It is 86 degrees, which is about 80 degrees at 300 MHz. Therefore, in the conventional 90-degree hybrid circuit, the phase difference can be set to 90 degrees at one spot frequency, but the phase difference of each signal output to ports P2 and P3 is adjusted to 90 degrees in a wide frequency band. There was a problem that it was difficult to do.

The object of the present invention is to solve the above problems, and it is possible to adjust the phase difference between the signals output to the ports P2 and P3 to a predetermined phase difference in a wide frequency band, and to operate in a wider frequency band than in the past. It is to provide a possible hybrid circuit.

[Means for Solving the Problems] A hybrid circuit according to the present invention is configured by winding at least two first and second single wires that are close to each other and form a set around a magnetic core, and the first single wire is provided. One end of is the input end,
The other end of the first single wire is the first output end, the one end of the second single wire on the input end side is the second output end, and the other end of the second single wire is the first output end side. In a hybrid circuit in which the other end is used as a load end, the load end is terminated by a load circuit having a reactance impedance for correcting the phase difference between the signals output to the first and second output ends. It is characterized by having done.

In the hybrid circuit, the at least two single wires are bifilar windings. Further, a first capacitor is connected between the input end and the second output end, and a second capacitor is connected between the first output end and the load end. To do.

Further, in the hybrid circuit, the at least two single wires are trifilar windings.

Further, in the hybrid circuit, the magnetic core is a toroidal core or a glasses-type core.

[Operation] In the hybrid circuit configured as described above, at least two first and second single wires are wound around the magnetic core,
A high frequency transformer is constructed in which the primary winding of the first single wire and the secondary winding of the first single wire are mutually inductively coupled with a coupling degree M.
At this time, the inductance LL1 of the primary winding has a value obtained by adding the inductance component kM · L1 · L2 due to mutual induction coupling to the inductance L1 of the first single wire. On the other hand, 2
The inductance LL2 of the secondary winding is the inductance component kM due to the mutual induction coupling to the inductance L2 of the second single wire.
・ L1 ・ L2 is added value. That is, it is expressed by the following equation.

LL1 ＝ L1 ＋ kM ・ L1 ・ L2 ・ ・ ・ (1) LL2 ＝ kM ・ L1 ・ L2 ＋ L2 ・ ・ ・ (2) where k is a positive proportional coefficient.

By the way, the coupling degree M of the high frequency transformer is 1 in the ideal case of tight coupling, but at this time, for example, the load end has the same characteristic impedance as the input end and the first and second output ends. When it is terminated with a resistor having a value of, the phase difference between the signals output from the first and second output terminals becomes constant at a predetermined phase difference. However, in reality, the degree of coupling M
Is a value slightly smaller than 1 such as 0.98. Therefore, at this time, the inductance LL1 of the primary winding decreases from the ideal value, and the inductance LL2 of the secondary winding also decreases from the ideal value. In order to compensate for this, a load circuit having a reactance impedance is connected to the load end. That is,
The load circuit is connected to the second single wire and the first
The load circuit is connected to the single wire. As a result, when the coupling degree M of the high frequency transformer is substantially equal to 1, the phase difference between the signals output from the first and second output terminals can be substantially corrected to a predetermined phase difference. .

Therefore, in the hybrid circuit, when a high frequency signal is input to the input terminal which is one end of the first single wire, the input high frequency signal is divided into two, and each two-divided signal is divided into two signals of the first single wire. The phase difference between the respective output signals becomes a predetermined phase difference of, for example, 90 degrees between the first output end which is the other end and the second output end which is one end on the input end side of the second single wire. Can be output as

Here, since the load end, which is the other end of the second single wire, is terminated by the load circuit having the reactance impedance, the first and second load lines are connected by this load circuit.
It is possible to correct the phase difference of each signal output to the output terminal of the above, and the phase difference of each signal output to the first and second output terminals is, for example, 90 over a wider frequency band than the conventional one. It becomes easy to adjust to a predetermined phase difference, which is a degree, whereby a hybrid circuit that can operate in a wide band can be realized.

Embodiments Embodiments according to the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a 90-degree hybrid circuit which is an embodiment of the present invention. The same components as those in FIG. 4 are designated by the same reference numerals.

The 90-degree hybrid circuit of this embodiment is different from the conventional 90-degree hybrid circuit shown in FIG. 4 in that the load connected to the port P4 is replaced by the resistor R _L and the resistor R ₀ and the inductor L ₀ are connected in series. That is, the loaded load circuit 20 is used.

The 90-degree hybrid circuit of this embodiment includes two inductors L1 and L1, which are closely arranged in a toroidal core.
The bifilar windings that make up 2 are wound and the inductor L
A capacitor C1 is connected between the respective ends of 1 and L2, and a capacitor C2 is connected between the respective other ends of the inductors L1 and L2. Here, both ends of inductor L1 are designated as ports P1 and P2, respectively, and both ends of inductor L2 are designated as ports P1 and P2, respectively.
3, and P4, the port P2, P3 with is grounded via a terminating resistor R _L2, R _L1, port P4, the resistance R ₀ and the inductor L ₀ is connected in series, the reactance of the impedance Z _L = It is grounded via a load circuit 20 having R ₀ + JωL ₀ . The numerical values of the resistance R ₀ and the inductor L ₀ of the load circuit 20 are selected so that the phase difference between the signals output to the ports P2 and P3 is approximately 90 degrees over the wide band.

In the hybrid circuit configured as described above, the bifilar windings that form the inductors L1 and L2 are wound to form a high frequency transformer in which the inductors L1 and L2 are mutually inductively coupled with the coupling degree M. At this time, the inductance LL1 of the primary winding on the inductor L1 side has a value obtained by adding the inductance component kM · L1 · L2 due to mutual induction coupling to the inductance of the inductor L1. On the other hand, the inductance LL2 of the secondary winding on the inductor L2 side
Is a value obtained by adding the inductance component kM · L1 · L2 due to mutual induction coupling to the inductance of the inductor L2. That is, it is expressed as in (1) and (2) above.

By the way, the coupling degree M of the high frequency transformer is 1 in the ideal case of tight coupling, but at this time, for example, if the port P4 is terminated by a resistor having the same characteristic impedance as the ports P1, P2, P3, The phase difference between the signals output from P2 and P3 is constant with a predetermined phase difference of 90 °. However, in reality, the degree of coupling M is a value slightly smaller than 1 such as 0.98. Therefore, at this time, the inductance LL1 of the primary winding decreases from the ideal value, and the inductance LL2 of the secondary winding also decreases from the ideal value. To compensate for this, port P4
A load circuit having a reactance impedance is connected to. That is, the load circuit is connected to the inductor L2, and the inductor L1 is connected via the capacitor C2.
The load circuit is connected to. This allows
This is almost equivalent to the case where the coupling degree M of the high frequency transformer is 1, and the phase difference between the signals output from the ports P2 and P3 can be substantially corrected to a predetermined phase difference.

In the 90-degree hybrid circuit of this embodiment, when a high-frequency signal is input to the port P1 from the high-frequency signal oscillator 10 having an output resistance R _S equal to the characteristic impedance Z ₀ , the high-frequency signal is divided into two and distributed to the ports P2 and P3. Each output signal having a phase difference of 90 degrees is output. Here, the load circuit 20
Operates as a device that performs phase correction so that the phase difference between the signals output to the ports P2 and P3 is approximately 90 degrees over a wide frequency band.

The present inventor has wound a toroidal core made of carbonyl iron having an outer diameter of 2 mm, an inner diameter of 0.7 mm and a thickness of 5 mm with a bifilar winding having a core wire diameter of 0.15 mm for 3 turns and having a capacitance of 5 pF.
Capacitor C1 and the capacitor C whose capacitance is 5 pF
After connecting 2 and the 90 degree hybrid circuit of the present embodiment shown in FIG. 1, a load circuit in which a resistor R ₀ of 180Ω and an inductor L _{0 of} 39nH are connected in series to the port P4. 20 to connect the forward transfer coefficient S ₂₁ between the ports P1 and P2, the forward transfer coefficient S ₃₁ between the ports P1 and P3, and the port P for the hybrid circuit.
2 and the phase difference of each signal output to P3 were measured.

FIG. 5 shows the frequency characteristics of the forward transfer coefficients S ₂₁ and S ₃₁ of the 90-degree hybrid circuit of the present embodiment shown in FIG. 1 and the frequency characteristics of the phase difference between the signals output to the ports P2 and P3. It is a graph shown.

As is clear from FIG. 5, the phase difference between the signals output to the ports P2 and P3 is almost constant over a wide frequency band from about 150 MHz to about 400 MHz. At frequencies above 100 MHz, the amplitude difference between the signals output to ports P2 and P3 increases as the frequency increases, but the amplitude levels of these signals should be easily adjusted using conventional methods. You can

As described above, by connecting the load circuit 20 having a reactance impedance to the port P4, the phase difference between the signals output to the ports P2 and P3 is set to 90 degrees over the wide band in comparison with the conventional example. can do. Therefore, a 90-degree hybrid circuit that can be used in a wide band can be constructed.

In the above embodiments, the bifilar winding is wound around the toroidal core to form a 90-degree hybrid circuit, but the present invention is not limited to this, and as shown in FIG. 2, a toroidal core or a glasses-type core is used. Alternatively, the trifilar windings may be wound close to each other and formed of three single wires to be wound. In this modification, the trifilar windings form inductors L11, L12, L13, one end of which is connected to the port P1 and the other end of which is connected to the port P2. The inductors L12 and L13 are connected in parallel, one end of which is connected in parallel is connected to the port P3, and the other end is connected to the port P4.

In the above embodiments, a circuit in which the resistor R ₀ and the inductor L ₀ are connected in series is used as the load circuit 20, but the present invention is not limited to this, and is shown in FIGS. 3 (A) to 3 (D). You may use using such a load circuit. That is, as the load circuit, as shown in FIG. 3 (A), a circuit in which a resistor R ₀ and an inductor L ₀ are connected in parallel may be used, or as shown in FIG. 3 (B), a resistor may be used. A circuit in which the resistor R ₀₂ is connected in parallel to the circuit in which R ₀₁ and the inductor L ₀ are connected in series may be used. Further, as the load circuit, to a third view inductor L ₀₁ and resistor R ₀ as shown in (C) may be using the circuit the inductor L ₀₂ in circuits connected in series are connected in parallel, the third Resistor R ₀ and inductor as shown in Fig. (D)
A circuit in which the inductor L ₀₁ is connected in series to the circuit in which L ₀₂ is connected in parallel may be used.

Further, in the 90-degree hybrid circuit shown in FIG. 1, when the capacitance between the inductors L1 and L2 is large,
The capacitors C1 and C2 may be omitted.

Although the 90-degree hybrid circuit is described in the above embodiments, the present invention is not limited to this, and the input signal is
The present invention can be applied to a hybrid circuit that divides the output signals into two so that the phase difference between the output signals becomes a predetermined phase difference.

In the above embodiments, when a signal is input to the port P1, the distributor that outputs each signal having a phase difference of 90 degrees to the ports P2 and P3 is described, the hybrid circuit according to the present invention However, the present invention is not limited to this, and may be used as a combiner that outputs signals obtained by inputting signals having a phase difference of 90 degrees to ports P2 and P3 and outputting the combined signals to port P1.

[Effects of the Invention] As described in detail above, according to the present invention, at least two first and second single wires that are close to each other and form a set are wound around a magnetic core. Of the second single wire as an input end, the other end of the first single wire as a first output end, one end of the second single wire on the input end side as a second output end, and the second single wire as described above. In a hybrid circuit in which the other end on the first output end side is used as a load end, the load end is provided with a reactance characteristic for correcting the phase difference between the signals output to the first and second output ends. Since it is terminated by the load circuit having impedance, the phase difference between the signals output to the first and second output terminals is adjusted to a predetermined phase difference of, for example, 90 degrees over a wider frequency band than the conventional one. It is easy to There is an advantage that it is possible to realize a work that can be hybrid circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a 90-degree hybrid circuit which is an embodiment according to the present invention, FIG. 2 is a circuit diagram of a 90-degree hybrid circuit which is a modified example of the embodiment of FIG. 1, and FIG. , FIG. 3 (B), FIG. 3 (C) and FIG. 3 (D) are circuit diagrams showing modified examples of the load circuit of the 90-degree hybrid circuit shown in FIG. 1 and FIG. 2, respectively. FIG. 4 is a circuit diagram of a conventional 90-degree hybrid circuit, and FIG. 5 shows the forward transfer coefficient and the frequency characteristic of the phase difference between the ports P2 and P3 of the 90-degree hybrid circuit of the present embodiment shown in FIG. FIG. 6 is a graph showing the frequency characteristics of the forward direction transfer coefficient and the phase difference between the ports P2 and P3 of the conventional 90-degree hybrid circuit shown in FIG. 20 …… Load circuit, L1, L2, L11, L12, L13, L ₀ ， L ₀₁ ， L ₀₂ ……
Inductor, C1, C2 …… Capacitor, R ₀ , R ₀₁ , R ₀₂ ……
Resistance, Z _L …… Load impedance, P1, P2, P3, P4 …… Port.

Claims (5)

[Claims] 1. A first core comprising at least two first and second single wires wound in a magnetic core around each other, wherein one end of the first single wire serves as an input end. Of the second single wire as the first output end, one end of the second single wire on the input end side as the second output end, and the other end of the second single wire as the first output end on the load end. In the hybrid circuit used as, the load end is terminated by a load circuit having a reactance impedance for correcting the phase difference between the signals output to the first and second output ends. Hybrid circuit to do. 2. The hybrid circuit according to claim 1, wherein the at least two single wires are bifilar windings. 3. A first capacitor is connected between the input end and the second output end, and a second capacitor is connected between the first output end and the load end. The hybrid circuit according to claim 2, wherein: 4. The hybrid circuit according to claim 1, wherein the at least two single wires are trifilar windings. 5. The hybrid circuit according to claim 1, 2, 3 or 4, wherein the magnetic core is a toroidal core or an eyeglass type core.