FI83003C - 180-GRADS HYBRIDKOPPLING. - Google Patents

Description

1 83003 180-degree hybrid coupling

The invention relates to a 180-degree hybrid circuit comprising an input and two outputs with a 180-5 degree phase shift relative to each other.

Certain applications, such as balanced mixers, require a 180-degree hybrid in which both the phase and amplitude balances between the different outputs or branches of the hybrid are very good or close to optimal over a wide frequency band. At high frequencies and microwave frequencies, such 180-degree hybrids, i.e. Baluns, are implemented mainly with microstrip structures such as Rat-Race, coupled wires, pair wire, coplanar, double-Lange switch, etc. For example, the Rat-Race structure 15 achieves a 10-degree phase balance and 1 dB amplitude balance in the frequency band of about 20%.

The article "Designing with the Double Lange Coupler," by Derek Fitzgerald, RF design, October 1988, pp. 46-48, presents a 180-degree 20 hybrid implemented with two Lange switches. It has two 90-degree Lange switches connected. . in series such that the transmitted signal of the series-connected hybrids is 180 degrees out of phase with respect to the input signal. As can be seen from Figure 5 of that article, the problem of such a hybrid coupling is also the poor amplitude and phase balance. Thus, they can only be used at point frequencies and not over a wide frequency range.

It is an object of the present invention to provide a 180 degree hybrid coupling in which the amplitude and phase ba-lance between the different branches are very good over a wide frequency range.

This object is solved by a hybrid circuit of the type described in the introduction, which according to the invention is characterized in that the hybrid circuit comprises 35 signal splitters and two mutually symmetrical 90-degree 2 83003 hybrid circuits, one connected to cause a + 90-degree phase shift and the other to -90 phase shift to produce two output signals with a 180 degree phase shift relative to each other.

5 Using two 90-degree hybrids and a 0-degree hybrid connecting them, two symmetrical phase shift branches are formed, resulting in very good amplitude and phase balance over the octave band. The invention is thus based on the applicant's finding that the problem with the known solutions has been their asymmetry, whereby the phase and amplitude balances change strongly as the frequency changes. In the solution according to the invention, both branches are symmetrical, in which case the frequency dependences of the branches are also substantially similar.

In the hybrid connection according to the invention, generally available components can be used, which are connected according to the invention in a new way.

Preferably, the hybrids are implemented with microstrip structures, with the additional advantage of being small in size and the possibility of fabricating a hybrid circuit by circuit board technology.

The invention will now be described in more detail with reference to the accompanying drawing, in which Figure 1 shows a hybrid circuit according to the invention in block diagram form, Figure 2 shows a hybrid circuit according to the invention implemented with a Wilkinson splitter and two Lange switches, and Figures 3 and 4 show the amplitude and balance of Figure 2 circuit. as a function of the frequency of the phase balance graph.

According to Figure 1, a 180-degree hybrid circuit according to the invention comprises an input IN and two outputs OUTI and OUT2 with a 180-degree phase shift relative to each other. The input of the hybrid circuit is formed by a 0-degree hyb-35 ridi or divider that divides the input signal into two of its 3 83003 in-phase outputs. A similar 90-degree hybrid 6 and 7 is connected to each output of the 0-degree divider.

Each 90-degree hybrid 6 and 7 comprises an input-5 input port 1, quadrature output ports 3 and 4, and an isolated output port 2. Normally connected, such a 90-degree hybrid causes the signal input to the input port 1 to be divided into two quadrature-phase signals which occur at output ports 3 and 4. An isolated output port 2 does not normally receive a signal and is usually terminated in a 50 ohm resistor.

In the hybrid circuit of the present invention, the input of the hybrid 6 is connected to the output 15 2 of the signal divider 5 and the output ports 3 and 4 are connected open so that a signal is formed in the isolated output port 2, which is the output of the hybrid circuit OUTI, + 90 degrees out of phase with the input signal. Correspondingly, the input port 1 of the hybrid 7 is connected to the second output port 3 of the signal divider 5 and the output ports 3 and 4 are connected to ground potential, so that an isolated output port 2, which is the second output OUT2 of the hybrid circuit, generates a signal with a phase shift of -90 degrees to the input signal. Thus, the hybrids 6 and 7 invert the phase of the input signal 90 degrees in opposite directions with respect to each other, and a phase difference of the outputs OUTI and 0UT2 can be formed 180 degrees. Since in the hybrid circuit according to the invention the hybrids 6 and 7 are symmetrical to each other, i.e. change in the same direction with respect to the frequency 30, the amplitude and phase balances between the different branches of the hybrid circuit remain very good in a wide frequency band.

Figure 2 shows a preferred embodiment of the invention, in which a Wilkin-35 son splitter is used as the 0-degree hybrid 5 and the Lange switch 4 83003 as microstrip structures as the 90-degree hybrids 6 and 7. The hybrid circuit of the invention shown in Figure 2 is on a natural scale, suitable for the frequency range of about 1.5-3.0 GHz. In addition, a dashed line 100 ohm resistor 5 is to be connected between the branches of the Wilkinson divider 5 in Fig. 2.

Figure 3 illustrates the amplitude balance of the hybrid switch field of Figure 2 as a function of frequency Ρουτι - Ρουτ2. Correspondingly, Fig. 4 shows the phase balance of the hybrid coupling field of Fig. 2 Φουτ1 to Φουτ 2 as a function of frequency. From the Ku-10 faults, it can be seen that a phase balance of 10 degrees and an amplitude balance of 1 dB are achieved in the frequency range of 1.5-3.3 GHz, i.e. in the over-octave band.

Various Lange switches and their properties are discussed, for example, in the above-mentioned 15 articles on RF design. General methods for making microstrip line hybrids are known to those skilled in the art.

Although the widest possible hybrids have been used in the preferred embodiment of the invention, the symmetrical 180-degree hybrid coupling according to the invention can in principle be implemented with any 90- and 0-degree hybrids.

The accompanying figures and the related description are intended to illustrate the invention only. The details of the hybrid coupling according to the invention may vary within the scope of the appended claims.

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Claims (5)

83003 1. A 180-degree hybrid circuit comprising an input (IN) and two outputs (OUTI, OUT2) with a 180-degree phase shift relative to each other, characterized in that the hybrid circuit comprises a signal divider (5) and two mutually symmetrical 90- a degree hybrid circuit (6, 7), one connected to cause a + 90 degree phase shift in the input signal and the other to a -90 degree phase shift to produce two output signals in a 180 degree phase shift relative to each other. 2. Hybrid copying according to claim 1, with 90 degree hybrid devices (6, 7) Sr av en typ, som om- fattar en ingängsport, en 0 graders utgängsport, en 90 graders utgängsport and en isolerad utgängsport, kännetecknad därav, att i 90 graders hyb-ridkretsen, som förorsakar en +90 graders fasförskjutning ät ingängssignalen, är 0 graders och 90 20 graders utgängsportarna kopplade öppna och den isole- ingängssignalen, 0 graders och 90 graders utgängsportarna är kopplade account en 25 jordpotential och den isolerade utgängsporten til en utgäng. Hybrid circuit according to claim 1, wherein the 90-degree hybrid circuits (6, 7) are of the type comprising an input port, a 0-degree output port, a 90-15-degree output port and an isolated output port, characterized in that the 90-degree hybrid circuit causing the input signal The + 90-degree phase shift, 0-degree, and 90-degree output ports are connected open and the isolated output port is output, while the other 90-degree hybrid circuits that cause the input signal are -90-degree phase shift, 0-degree, and 90-degree output ports are connected to ground potential and an isolated output port as an output. 3. Hybrid copying according to claims 1 or 2, which comprises a signal circuit (5) and a hybrid (6, 7) according to a microbial structure. Hybrid switching field according to Claim 1 or 2, characterized in that the signal splitter (5) and the hybrids (6, 7) are implemented with microstrip structures. 4. Hybrid copying according to claim 3, which comprises a signaling device (5) and a Wilkinson signaling device. Hybrid coupling according to Claim 3, characterized in that the signal divider (5) is a Wilkinson divider. Hybrid switch field according to Claim 3 or 4, characterized in that the 90-degree hybrids (6, 7) are Lange switches. 6 83003 1. 180 graders for hybrid copying, single phase (IN) and other devices (OUTI, 0UT2) with 5 sinks 180 graders for operation, reverse of the signal, hybrid copying and signaling (5) and symmetry 90 graders are hybrid characters (6, 7), which are not more than +90 graders in the range of +90 graders and 10 and more than -90 graders in the field of a single signal with 180 graders. 5. Hybrid copying according to claim 3 or 35 4, which comprises 90 graders of the hybrid (6, 7) and is lange-copying.