US 3714661 A
Description (OCR text may contain errors)
United States Patent [1 1 [111 3,714,661
Kershaw 1 Jan. 30, 1973  METHOD AND APPARATUS FOR 156] References Cited COUPLING MULTIPLE POWER a I SOURCES T0 SINGLE RADIATING UNITED STATES PATENTS ANTENNA 3,453,638 7/1969 Hoover ..333/ll Inventor: Joseph E. Kershaw, La Mesa, Calif.
The United States of America as represented by the Secretary of the Navy Filed: Jan. 24, 1972 Appl. No.: 219,999
US. Cl. ..343/858, 333/10, 333/11 Int. Cl. ..H0lq 1/50 Field of Search ..343/850, 854, 858; 333/11 Primary ExaminerEli Lieberman Att0rneyR. S. Sciascia et al.
A single antenna can be used to radiate power from multiple power sources having a wide, composite frequency band. Frequency-related pairs of the sources are combined in input hybrid junction devices. The combined outputs thereof are re-combined in successive hybrid junctions. The re-combined outputs are combined a last time in an output hybrid junction to produce a wide band output.
ABSTRACT 2 Claims, 1 Drawing Figure METHOD AND APPARATUS FOR COUPLING MULTIPLE POWER SOURCES TO SINGLE RADIATING ANTENNA BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION A method for combining up to eight signals for wideband radiation by a single antenna is disclosed. The signals are applied in frequency-related pairs to the E and H input ports of hybrid junctions having a frequency band which includes the frequency of the two particular signals applied thereto. Each of the hybrid junctions combines the two signals applied at its input ports and divides the combined signals equally at two output ports, one of which is terminated. The unterminated,
combined outputs from each junction-are applied again in frequency-related pair to another hybrid junction where these two outputs are in turn combined. The process is used repetitively to combine up to eight oscillator outputs for radiation by a single antenna. The final hybrid junction frequency band includes the frequency range for each of eight signals. The power sources may be at any frequency within the bandwidth of the hybrids and may be at any phase with respect to each other.
OBJECTS OF THE INVENTION It is a primary object of the inventive concept to be disclosed herein to disclose a method using hybrid junction devices for combining multiple power sources for radiation by a single antenna over a wide frequency band.
It is another object of the present invention to dis close a novel technique using hybrid junctions whereby a plurality of different frequency power sources can be combined for radiation by a single antenna and which is especially advantageous in the limited space environment such as on a naval ship.
Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING The drawing is a simplified block diagram of the novel power source combination technique using hybrid junction devices to be disclosed herein.
DESCRIPTION OF THE PREFERRED EMBODIMENT The inventive concept which relates to RF circuitry and which is to be disclosed herein is best illustrated by the simplified block diagram of the FIGURE. In the FIGURE, eight different power sources P P P P,,, P P P and P having different frequencies f1, f2, f3, f4, f5, f6, f7 and f8, respectively, are shown being applied in consecutive, frequency-related pairs to the input hybrid junctions 10, l2, l4, and 16, respectively, at the E and H ports thereof.
The two signals or signal pair applied to each different hybrid junction each have a different frequency within the frequency range of the corresponding hybrid junction. Thus the frequency range of a transmitting system using the concept disclosed herein can encompass the frequency range f1-f8 covered by the individual power sources.
The output of each power source or oscillator can be connected to the input port of its associated hybrid junction by attenuator means (not shown). If used, the attenuators are located between the oscillator outputs and the input ports to increase the isolation between the oscillators by providing improved terminations for the hybrids and also by providing a direct increase in isolation equal to the value of the attenuators.
Each hybrid junction produces two outputs at the output ports which are designated in the art as ports I and 2. As can be seen, each of the output ports 2 are terminated in a suitable impedance. The output signal at each of the input hybrid junctions output port 1 is proportional to the sum of the two input signals. The combined signal outputs from the two input hybrid junctions wand 12 are coupled to the E and H ports of a succeeding junction 20 having a frequency band which includes the frequencies fl, f2, f3, and f4.
Again attenuators can be used between the output ports of the input ports of the successive hybrid junction 20 for the reasons given above. Likewise, the output port 2 of the hybrid junction 20 is terminated at 18 and at the other output port 1, the output signal is proportional to the four signals applied to the first two input hybridjunctions l0 and 12.
The same technique or method is used with respect to the two other hybrid junctions l4 and 16 to combine the power sources P P P and P The output of the succeeding hybrid junction 22 is thus an output signal which is proportional to the combination of the power sources P, P P, and P Finally, the outputs of the two successive hybrid junctions 20 and 22 are coupled to the E and H ports of an output hybrid junction 24 whose frequency band must include the frequencies f1, f2, f3, f4, f5, f6, f7, and f8. The unterminated output at the port 1 of the output hybrid coupler 24 represents a combination of the aforementioned eight input signals or power sources and since each coupler or junction divides the input power equally at its two output ports it can readily be shown that the output signal of the junction 24 has a magnitude substantially equal to any one of the power sources if they are of equal magnitude, but the output signal obviously has a frequency band equal to fl f8. Thus the output of the output hybrid coupler 24 can be connected using conventional RF techniques to a common antenna 26 for radiation of the power sources over a wide frequency band.
The hybrid junctions shown in the triangular networ in the FIGURE comprise well-known, four-port networks capable of splitting input signals into equal amplitude, isolated outputs which are either in phase or out of phase by 180. These networks are known in the microwave community under such names as Magic Tees, Rat Race Hybrids, Ring Hybrids, and Hybrid Tees, sum and difference hybrid, balanced hybrid, symmetric hybrid, and comparator hybrid.
Operationally, signals fed-to the H, or symmetric port, will split equally and in phase between the colinear output ports 1 and 2. Likewise, signals fed to the E, or anti-symmetric port, will also split equally between ports 1 and 2 but will be 180 out of phase. This in-phase and out-of-phase relationship results in isolation between the E and H ports. Simultaneous application of signals to both H and E ports results in the vector thereof addition at one colinear port and vector subtraction thereof at the other. Commercially available hybrid junctions cover the various frequency ranges between audio and X band and perform over an octave or more of bandwidth.
According to the method described above, each hybrid combines the signals provided at the input ports and divides the input power equally between ports E and H. Neglecting losses, the power P, at frequency f1 applied on a single coaxial line at a hybrid junction 10 input port E and the power P at frequency f2 applied at the input port H produces an output of k P, h P, watts at the output port 1 and A: P, and r5 P watts at the terminated port 2.
As shown in the FIGURE, the process can be used repetitively to combine up to eight oscillator outputs for radiation by a single antenna. Obviously eight other signals could be combined in the same manner a different number of times and the process repeated with the combined output signals thus obtained.
Thus it can be seen that a novel method for combining multiple power sources for radiation by a single antenna has been disclosed. The method permits a single antenna to be used over a wide frequency band encompassing the frequency range of the several power sources. The power sources to be combined may be fed .at any frequency within the bandwidth of the associated hybrid and may be at any phase with respect to any of the other power sources. It is only necessary that each'power source be setto a frequency within the frequency band of the associated hybrid coupler.
The method disclosed herein is especially advantageous for use in limited space environments since only one antenna to transmit over a wide band. Furthermore, it is not necessary to retune a combining network as in the prior art, lengthy times for frequency shifting are eliminated, and for wideband power amplifiers are not required. Obviously there is also a cost advantage over the prior art.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. A method for combining four pairs of power sources having different frequencies for radiation by a single antenna comprising the steps of:
combining each of said pairs in a different one of 5 four input hybrid junctions to produce at the outut of each one thereof an output signal substanially equal to one-half the power the applied pair;
combining said output signal from each of said four input hybrid junctions in pairs in two succeeding hybrid junctions to produce at the outputs thereof two re-combined output signals substantially equal to one-half the power of the applied pair;
combining said two re-combined output signals in a final hybrid junction to produce a final output signal substantially equal to one-half the power of said two re-combined output signals; and, coupling said final output signal to common antenna means for radiation thereof over a frequency band which includes the frequency of each of said power sources.
2. A hybrid junction network for combining power sources P,, P P P P P P and P,,, at frequencies fl, f2, f3, f4, f5, f6, f7, and f8, respectively, for radiation by a single antenna over the frequency band flf8, comprising:
first, second, third and fourth input hybrid junctions having frequency bands which include the frequencies fl and f2, f3 and f4, f5 and f6, and t7 and f8, respectively;
means for coupling P, and P P and P P and P and P and P to the E and H ports of said first, second, third, and fourth input hybrid junctions, respectively;
impedance means connected to one of the two output ports of each of said input hybrid junctions; fifth and sixth successive hybrid junctions having frequency bands which include the frequencies fl, f2, f3 and f4, and f5, f6, f7, and f8, respectively; means for coupling the output from said first and second input hybrid junctions to the E and H ports of said fifth successive hybrid junction and for coupling the output from said third and fourth input hybrid junctions to the E and H ports of said sixth successive hybrid junction;
impedance means connected to one of the two output ports of each of said successive hybrid junctions; a seventh output hybrid junction having a frequency band which includes the frequencies f1, f2, f3, f4, f5, f6, f7, and f8,
means for coupling the output from. said fifth and sixth successive hybrid junctions to the E and H ports of said seventh output hybrid junction; impedance means connected to one of the two output ports of said output hybrid junction; and, means for coupling the output of said output hybrid junction to a common antenna.