GB2069244A

GB2069244A - Radio frequency zero phase power combiner

Info

Publication number: GB2069244A
Application number: GB8004491A
Authority: GB
Original assignee: Decca Ltd
Current assignee: Decca Ltd
Priority date: 1980-02-11
Filing date: 1980-02-11
Publication date: 1981-08-19
Also published as: AU6711581A

Abstract

A radio frequency zero phase power combiner in which the input terminals Pin1, Pin11 are connected to a common point by respective circuit branches each of which includes a ballast resistor RL1, RL2 and the primary of a current transformer of which the secondary feeds a rectifying and smoothing circuit. An out-of-balance input signal causes current flow in one or more of the ballast resistors and is detected by means of a circuit responding to the output of the rectifying and smoothing circuit. <IMAGE>

Description

SPECIFICATION Radio frequency zero phase power combiner This invention relates to a radio frequency zero phase power combiner. Such a combiner includes a plurality of input ports, one for each of the input signals which are to be combined in a common output and a matched coupling of each input port to a common output port. The connection between the input ports and the output ports may be a quarter wave length of coaxial line of which the inner conductor is split into splines, corresponding in number to the input ports.

It is ordinary practice to provide a ballast resistor between a common point and the distinctivetermin- al of each input port, the term "distinctive" referring to that terminal which is not connected in common to the common output terminal. Normally, all the input signals to a power combiner of the zero phase type are equal in amplitude and phase. There is thus no difference in potential between the two ends of each circuit branch connecting any distinctive input terminal to the aforementioned common point and there is therefore no power loss in the ballast resistors which are usually provided in those bran ches.

The object of the invention is to provide an improved radio frequency zero phase power com biner. According to the present invention a detector is provided for current in each of the aforementioned branches. The detector may be in the form of a transformer including a primary coupled in or be tween respective branches and having a secondary circuit including a detector.

Reference will now be made to the accompanying drawings of which: Figure 1 illustrates a two-way'power combiner; Figure 2 illustrates a two-way power combiner modified according to the present invention; and Figure 3 illustrates a five-way power combiner.

Figure 1 illustrates a two-way power combiner in which signals which should normally be equal in amplitude and phase are combined into a common output. The input terminals of the power combiner are constituted by, for the first port, a terminal 1 and earth and for the second combiner a terminal 2 and earth. The terminals 1 are connected to a terminal 3 of an output port of which the other terminal is earthed. The connection between the output and input ports may be physically constructed as pre viously described in a manner similar to that de scribed by Ernest J. Wilkinson in I.R.E. Transactions on Microwave Theory and Practice, January 1960, pages 116 et seq.

The sources feeding the input ports are repre sented by generators in series with respective resistors Ri,. The terminals 1 and 2 are connected to a common point A by means of ballast resistors RL and RL2 respectively; these resistors are normally equal.

If the input signals at the two ports are equal in amplitude and phase, the instantaneous voltage across the two ballast resistors is at all times zero and no current will flow through the point A. If however there is a difference in amplitude or phase in the two signals, current will flow through the point A. Figure 2 illustrates the combiner of Figure 1 modified by the addition of a current transformer 3 between the two circuit branches that are constituted by the ballast resistors. Any current resulting from imbalance of the input signals will induce a voltage in the secondary winding of the transformer and produce an output which is rectified by the detector 5.

if the combination of more than two input signals is required, there would normally be a corresponding plurality of ballast resistors each connected between a common point, which is not earthed, and the distinctive (non-earthed) terminal of each input port. Figure 3 shows such a combiner arranged to combine five input signals, which if identical in magnitude and phase induce no current flow in any ballast resistor. Disparity between any input signal and the other input signals causes current flow in one or more of the ballast resistors. The conditon of imbalance is detected by one or other of the current transformers which are provided in the respective circuit branch which the respective ballast resistor forms part.

1. A radio frequency zero phase power combiner of which distinctive input terminals are connected to a common point by respective circuit branches including ballast resistors and in which a detector is provided for current in each of the aforementioned branches.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Radio frequency zero phase power combiner This invention relates to a radio frequency zero phase power combiner. Such a combiner includes a plurality of input ports, one for each of the input signals which are to be combined in a common output and a matched coupling of each input port to a common output port. The connection between the input ports and the output ports may be a quarter wave length of coaxial line of which the inner conductor is split into splines, corresponding in number to the input ports.

It is ordinary practice to provide a ballast resistor between a common point and the distinctivetermin- al of each input port, the term "distinctive" referring to that terminal which is not connected in common to the common output terminal. Normally, all the input signals to a power combiner of the zero phase type are equal in amplitude and phase. There is thus no difference in potential between the two ends of each circuit branch connecting any distinctive input terminal to the aforementioned common point and there is therefore no power loss in the ballast resistors which are usually provided in those bran ches.

The object of the invention is to provide an improved radio frequency zero phase power com biner. According to the present invention a detector is provided for current in each of the aforementioned branches. The detector may be in the form of a transformer including a primary coupled in or be tween respective branches and having a secondary circuit including a detector.

Reference will now be made to the accompanying drawings of which: Figure 1 illustrates a two-way'power combiner; Figure 2 illustrates a two-way power combiner modified according to the present invention; and Figure 3 illustrates a five-way power combiner.

Figure 1 illustrates a two-way power combiner in which signals which should normally be equal in amplitude and phase are combined into a common output. The input terminals of the power combiner are constituted by, for the first port, a terminal 1 and earth and for the second combiner a terminal 2 and earth. The terminals 1 are connected to a terminal 3 of an output port of which the other terminal is earthed. The connection between the output and input ports may be physically constructed as pre viously described in a manner similar to that de scribed by Ernest J. Wilkinson in I.R.E. Transactions on Microwave Theory and Practice, January 1960, pages 116 et seq.

The sources feeding the input ports are repre sented by generators in series with respective resistors Ri,. The terminals 1 and 2 are connected to a common point A by means of ballast resistors RL and RL2 respectively; these resistors are normally equal.

If the input signals at the two ports are equal in amplitude and phase, the instantaneous voltage across the two ballast resistors is at all times zero and no current will flow through the point A. If however there is a difference in amplitude or phase in the two signals, current will flow through the point A. Figure 2 illustrates the combiner of Figure 1 modified by the addition of a current transformer 3 between the two circuit branches that are constituted by the ballast resistors. Any current resulting from imbalance of the input signals will induce a voltage in the secondary winding of the transformer and produce an output which is rectified by the detector 5.

if the combination of more than two input signals is required, there would normally be a corresponding plurality of ballast resistors each connected between a common point, which is not earthed, and the distinctive (non-earthed) terminal of each input port. Figure 3 shows such a combiner arranged to combine five input signals, which if identical in magnitude and phase induce no current flow in any ballast resistor. Disparity between any input signal and the other input signals causes current flow in one or more of the ballast resistors. The conditon of imbalance is detected by one or other of the current transformers which are provided in the respective circuit branch which the respective ballast resistor forms part.

1. A radio frequency zero phase power combiner of which distinctive input terminals are connected to a common point by respective circuit branches including ballast resistors and in which a detector is provided for current in each of the aforementioned branches.