US3594797A

US3594797A - Combination push-pull amplifier and antenna

Info

Publication number: US3594797A
Application number: US808029*A
Authority: US
Inventors: Eugene F Pereda
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-09-27
Filing date: 1968-09-27
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20

Abstract

A dipole antenna connected across the input of a transistorized push-pull amplifier. The output of the amplifier is applied to a conventional small RF receiver. A first embodiment includes a filter network connected to the antenna for supplying bias voltage to the amplifier. A second embodiment includes a DC battery for supplying the bias.

Description

[56] References Cited United States Patent [72] Inventor Eugene F. Pereda 460 Electric Ava, Seal Beach, Calif. 90740 808,029

Sept. 27, 1968 July 20, I971 [21] Appl. No. [22] Filed [45] Patented [54] COMBINATION PUSH-PULL AMPLIFIER AND ANTENNA ZChims, ZDIIIiIg Fi s.

, 325/373' [51] 1nt.Cl ..1101g1/Z6. H01g9/l6 [50] Field olSearch 343/?QQ UNlTED STATES PATENTS 2,268,639 1/1942 Blfldfitl 2,578,973 12/1951 Hills 343/816 X 3,475,759 10/1969 Winegard... 343/882 X 2,679,001 5/1954 Tomcik 325/384 3,098,973 7/1963 Wickersham, Jr. et a1. 343/793 X 3,496,566 2/1970 Walter et a1. 343/793 X OTHER REFERENCES Radio Waves Power Transistor Circuits," L. R. Crump in ELECTRONICS engineering edition, May 9, 1958; pages 63- 65 Primary Examiner-l-lerman Karl Saalbach Assistant Examiner-Marvin Nussbaum Attorneys Clarence A. OBrien and Harvey B. Jacobson WTRACT: A dipole antenna connected across the input of a transistorized push-pull amplifier. The output of the amplifier is applied to a conventional small RF receiver. A first embodiment includes a filter network connected to the antenna for supplying bias voltage to the amplif er. A second embodi- 1mm includes a DC battery for supplying the bias.

PATENTEU JUL20 197:

Fig.

Eugene E Pereda I l I Ink Ann-q:

COMMINA'IION IUSI'I-IIJLI. Alt IILIFIIEII AND ANTENNA This invention relates generally to the electronic art and more particularly to a device incorporating the characteristics of an antenna and amplifier to provide a high gain for FM or video signals before the signals are fed to a conventional receiver.

Many areas of our country are situated in a remote location relative to video and FM transmitters. Therefore, reception in these areas has generally been rather poor. Consequently, numerous research projects have devoted themselves to the development of antenna for improving the basic characteristics gain, directivity, and construction. In the present application we are principally concerned with the first and third characteristics. The research projects noted above have been successful in developing improved antenna construction for improving the characteristics noted. However, the development has resulted in complex and cumbersome antenna devices which apparently have inherent undesirable charac-- teristics.

Accordingly, the applicant has herein developed a device which is of relatively simple construction and which displays excellent gain and construction characteristics. It is the rincipal object of this invention to provide a novel amplifier-an tenna combination for improving video and FM reception in weak signal areas.

It is a further object of this invention to provide a novel amplifier-antenna combination which is less complex, thereby presenting improved structural features, and which further more efficiently utilizes received electromagnetic signals.

In accordance with the above stated objects, the invention below disclosed incorporates a push-pull transistor amplifier with a dipole antenna and utilizes particular desirable features of each to obtain a significantly improved device. More particularly, it is known that the antenna feed point on the driven element of a conventional dipole antenna is a point of low im pedance and maximum current. Therefore, taking cognizance of this characteristic, the present invention utilizes the current maximum for feeding a common emitter transistor amplifier circuit. lt is well known that transistors are current controlled and therefore particularly adapted to be fed from the antenna feed point on the driven element. The output of the push-pull transistor amplifier is inductively coupled through a transmission line, generally of 300 ohm impedance, to such, as a conventional television receiver, or the like. Further, the most apparent special characteristic of a transistor amplifier is its minimal size. This characteristic enables the amplifier to be closely packaged adjacent the driven element whereby the appearance and construction of the antenna will not be adversely affected. It is further contemplated that the antenna be plastic coated for increasing its resistance to shock, bending, vibration and moisture. Due to the particular nature of the device, it is well adapted to be economically constructed utilizing automatic assembly procedures. The construction so far discussed enables the antenna to operate at about 80 db. higher than a similar untransistorized dipole antenna. Therefore, the invention is adapted to be favorably utilized indoors.

Of course, an amplifier power supply is necessary for the amplifier to properly operate on the signals received by methods as shown in the two embodiments particularly disclosed in the specification below. Initially, the first embodiment utilizes the reflector element for supplying power to the amplifier. The reflector element is electrically connected to a filter circuit and thereafter to the amplifier for providing the necessary power thereto. In this embodiment, it will be noted that the invention has the advantage of being strictly passive until the antenna construction receives electromagnetic waves which provide the input signal and the power to the amplific rantenna combination. A second embodiment utilizes flashlight cells to power the amplifier. ln either embodiment, of course, the reflector element serves its conventional function of reflecting electromagnetic signals to the driven element for transmission to the receiver.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. I is a schematic diagram of one embodiment of the invention wherein the reflector element supplies the amplifier power; and

FIG. 2 illustrates a second embodiment of the invention wherein a pair of battery cells are shown supplying amplifier power.

With continuing reference to the drawing and initial reference to FIG. I, the numeral 10 generally represents the amplifier-antenna combination wherein the numeral 12 designates the driven element of a conventional dipole antenna assembly wherein the antenna feed point is generally taken between points M and to. The numeral 1% indicate the reflector elements of the dipole antenna and each of the elements is equal to one-half a wave length with a spacing between the elements of approximately one-quarter wave length. Across the antenna feed points 14! and I6 are connected a pair of signal resistors 20 and 22. Further, a pair of

transistors

24 and 26 have their bases 2% and 3t) electrically connected to the driven element at the points Id and I6. Bias resistors which are preferably variable are illustrated at 32 and 34 connecting the respective bases 2% and 30 to respective collectors 36 and 3d of the transistors 2d and 26. The emitters A0 and 42 of the transistors 24 and 2e are electrically connected to a common point Ml which is in turn electrically connected to resistor 46 at the midpoint 438 between the signal resistors 20 and 22.

The reflector element 118 is connected to filter circuit Sill through series diode 52, series resistor 54! and parallel capacitors as and 58. lPower is supplied to the amplifier between common point M, between the emitters 430 and A2 and junction so at the output coil 62 electrically connected across the collectors as and 3b. The output coil 62 forms the primary of a transformer Ml having a core 66 and secondary winding 68 which supplies the conventional receiver. It will be apparent that a push-pull transistor amplifier has been illustrated wherein the input signal is derived across the signal resistors 2d and 22 and the power supply is impressed across the points' 4A and tit). The amplifier output is transformed from output or primary winding 62 to the secondary winding 68 which in turn feeds the receiver. Values of individual components have been omitted in that it is felt that these are merely design considerations and particularly subject to the signals one desires to receive and the degree of amplification required.

FIG. 2 illustrates a second embodiment of this invention wherein basically identical principles are utilized. However, in lieu of the filter circuit 50 connected to the reflector elements III in FlG. I for supplying power between points 45% and 60 of FIG. 1, a pair of serially connected batteries 70 and 72 are utilized to impress the power voltage across points AA and 60 in FIG. 2. The cells '70 and 72 may be supported within a weatherproof casing "M adjacent the antenna mounting or wherever convenient. It is apparent therefore that the embodiment of FIG. it utilizes a completely passive circuit whereas the embodiment of FIG. 2 requires this inclusion of the active batteries 7i) and 72.

It will of course be apparent to those skilled in the art how to modify the circuits of the present invention by replacing the transistors with operational equivalents such as FETs (field effect transistors), unencapsulated transistors and the like.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes may readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

I claim:

El. An antenna assembly comprising driven elements having respective feed points, a push-pull solid-state amplifier having input terminals connected to the feed points through an electrically direct path, and tap-off tenninals connected to the amplifier output for making available amplified electromagnetic signals for utilization by a receiver front end section, reflector elements positioned in spaced relation to the driven elements, the antenna assembly further including means for converting alternating current to direct current, means connected between the reflector elements and the input of the converter means for supplying received radiation power to the converter means, and means for connecting the output of the converter means to the power input terminals of the amplifier for delivering biasing power thereto.

2. An antenna assembly with a self-contained signal amplifier comprising an antenna assembly having at least a pair of driven elements and a pair of reflector elements, a pair of solid-state devices connected in a push-pull amplifier configuration, the devices as having input terminals respectively connected to the feed points of the driven element through an electrically direct path, a biasing circuit connected to the solid-state devices and power converting means connected between the reflector element and the biasing circuit for delivering biasing power thereto, the reflector elements supplying received radiation power to the converting means, the converting means including first and second input terminals connected to respective reflector elements, a diode serially connected to the first input terminal, and an RC pi filter network connected in circuit between the input terminal and the biasing circuit.

Claims

1. An antenna assembly comprising driven elements having respective feed points, a push-pull solid-state amplifier having input terminals connected to the feed points through an electrically direct path, and tap-off terminals connected to the amplifier output for making available amplified electromagnetic signals for utilization by a receiver front end section, reflector elements positioned in spaced relation to the driven elements, the antenna assembly further including means for converting alternating current to direct current, means connected between the reflector elements and the input of the converter means for supplying received radiation power to the converter means, and means for connecting the output of the converter means to the power input terminals of the amplifier for delivering biasing power thereto.