US2673930A - Ultrahigh-frequency crystal device of the asymmetrical conductivity type - Google Patents

Description

March 30, 1954 H. F'. MATARE ULTRAHIGH-FREQUENCY CRYSTAL DEVICE OF THE 2,673,930

ASYMMETRICAL CONDUCTIVITY TYPE Filed Aug. 11, 1949 Patented Mar. 30, 1954 ULTRAHIGH-FREQUEN CY CRYSTAL DEVICE OF THE ASYMMETRICAL CONDUCTIVITY TYPE Herbert Francois Matar signor to Societe A Vaucresson, France, asnonyme dite:

Compagnie des Freins et Signaux Westinghouse, Paris,

France Application August 11, 1949, Serial N 0. 109,753 Claims priority, application France August 8, 1948 3 Claims.

This invention relates to high frequency crystal diodes or detectors of the kind now widely utilized for frequencies above 3,000 me. such as would correspond to the upper portion of the S, X and more particularly K bands (the K band comprising the waves of the order of centimeter).

It is known that the ultra. high frequency crystal detectors of this type developed heretofore, have a number of drawbacks which may be divided Fig. 1 represents a perspective view of a ultra high frequency crystal detector according to the invention, and

Fig. 2 a longitudinal section of the same device, at an enlarged scale.

Referring to the drawings, l represents a wave guide corresponding to the frequencies utilized, having standard connecting flanges 2. Crystal detector unit 3 is arranged at right angle to the into two groups, constructional and radioelectric. 1O longitudinal axis of wave guide I.

The first group of drawbacks results from the Crystal detector unit 3 itself, as apparent from extreme smallness of the component parts. Han- Fig. 2, consists of a barrier-layer semi-conductor dling and assembling operations are difiicult and l, which is supported on tip member 5, and enthe manufacture of the device is costly. gaged by point member 6 which connects with a It is impossible to remove such component second tip member 1, the barrier layer engaged parts, in contrast to the devices used for waveby point member 6 being positioned centrally of lengths above 10 cm. where, among other removguide tube I. able elements, the detecting member is made ex- Each of the tip members 5 and 1 consists of a changeable. In the present range, the fixed screw-threaded rod engaging a corresponding inmounting of the component parts precludes any ternally screw-threaded socket 8 mounted in a possibility of adjustment. washer 9 of insulating material which may be of The second group of drawbacks results from the type known under the trade name of Trodielectric losses of members which act as insulalitul or of polystyrene or any other equivalent tors and are arranged in parallel with a barrier plastic, or even of a material like ultra high frelayer. The derivated currents increase as a result quency ceramic. Washer 9 is held inside a conof the insulators associated with the contact elecnecting tube It secured in any suitable manner trodes. This results in a shunting factor which to guide tube 1. Washer 9 also serves to center is hardly acceptable in an asymmetrical conducsocket 3 and thereby tip member 5 or 1. tivity device. Another ring-shaped member I l, which consists If coaxial connections are used, since the critiof metal, is mounted on socket 8 and it serves to cal diameter for coaxial lines having normal imadjust output capacitance. By varying the diampedance characteristic is about 0.5 0111., this type eter of ring it the output capacitance may be of connection is obviously unsuitable for waveadapted to specific conditions of utilization. lengths of the order of centimeter (see Borgnis, Ring it is held in position by means of another "Elektrische Nachrichten Technik, 1940, p. 47: insulating washer 12 (which may be of the same Die Konzentrische Leitung als Resonator). material as washer 9) and an internal screw The output capacitances have a fixed and dethread socket 13 which may be screwed around termined value and therefore cannot be adapted connecting tube l0. Washer 12 also serves to to variable conditions of utilization. One'of the center socket 8. objects of this invention relates to a circuit ele- 4 For positioning sockets 8 in the assembly dement for ultra high frequencies in which these scribed above, the sockets are provided with an drawbacks are reduced, if not eliminated. external thread and screwed into the central A more specific object of the invention is a deopening of metal ring it. This opening is provice comprising a wave guide corresponding to vided with an internal screw-thread. However the frequenciesemployed and a crystal diode unit any other suitable connection may be used withmounted in a direction substantially at right out exceeding the scope of the invention. angle to the longitudinal axis of said wave guide Similarly, socket 8, instead of being secured to and having electric characteristics adaptable to metal ring ll, may be secured to insulating the limits corresponding to the frequencies emwasher 9 by any suitable means (such as screwployed. 5n ing). The latter would be particularly conven Other features and advantages of the invention ient where the selected output capacitance should will appear from the specification in connection result in omission of metal ring H. In this case, with the accompanying drawings which illustrate socket 8 would form an adequate capacitance in a preferred embodiment of the invention in diarelation to external tube It. grammatical fashion by way of example only. It will be noted that semi-conductor 4 may be In the drawings:

mounted excentrically with respect to the end of screw 5. Thus it is possible by a simple rotation of screw 5, to scan the entire surface of semiconductor 4 to establish the point of optimum contact with point member 6.

By rotating and thereby displacing both screws 5 and I in axial direction, it will be possible to effect an adjustment for determining the pointsurface contact of optimum output. After such adjustment, sockets 8 may be filled with any suitable body such as wax in order to maintain adjustment.

Sockets 8 also act as output members to which suitable wires I4 (see Fig. 1) are attached, leading to utilization apparatus. Sockets 8 are readily adaptable to various purposes.

The unit described may be used for example as a mixer. For this purpose, a short-circuiting device is connected behind one of the two flanges 2. One of sockets 8 is connected to a local oscillator, the other serves as a medium-frequency output device.

Should the capacitance on the oscillator side be too high, a short-circuiting device would be placed on this side which could serve to match the detector within the guide member. The oscillator would be connected to another wave guide connected with the first mentioned guide member.

The assembly described above could also be used, for example, as a receiving rectifier. For this purpose, one output capacitance should be increased by modifying corresponding metal ring ll so that the low frequency may be taken off from one of the sockets 8; the other socket 8 remains short-circuited. There is also added a short-circuit behind the wave guide.

The asymmetrical conductivity unit described above has many advantages.

Firstly, it is composed of very simple parts of dimensions sufficient to facilitate handling and assembling.

Secondly, the dielectric losses are reduced to a value which renders them innocuous in relation to the operating frequencies because there are no losses in a direction parallel to the barrier layer.

Furthermore the device according to the invention is formed of removable and interchangeable parts,a requirement not met by present systems for wavelengths of the order of centimeter.

The device described consists of adjustable parts which make it possible to obtain the best possible output and to adapt the output capacitances to varying conditions of utilization.

Finally, coaxial operation occurs only after passing through the asymmetrical conductivity device. Thus, the drawbacks experienced with coaxial mountings such as used hitherto, in former devices, are avoided.

The constructional details of the device described and illustrated herein may be modified in various Ways without afiecting the spirit and scope of the invention.

What I claim is:

1. Crystal assembly of the asymmetrical conductivity type, comprising a wave guide corresponding to the frequencies utilized a crystal element a surface of which is freely exposed to the waves guided by said wave guide, a flexible point member extending freely exposed to said waves and transversely of the longitudinal axis of said wave guide, said point member being in contact with the exposed surface of said crystal element, means adjustably supported on said wave guide and supporting said crystal element,

and means also adjustably supported on said wave guide and supporting said point member solely at its end remote from the contact with said crystal element; said crystal supporting means and said point member supporting means including respectively two electrode members and sockets supporting said electrode members in a position adjustable in a direction perpendicular to said longitudinal axis, thereby to form terminals for outside connections.

2. Crystal assembly of the asymmetrical conductivity type, comprising a Wave guide corresponding to the frequencies utilized a crystal element a surface of which is freely exposed to the waves guided by said wave guide, a flexible point member extending freely exposed to said waves and transversely of the longitudinal axis of said wave guide, said point member being in contact with the exposed surface of said crystal element, means adjustably supported on said wave guide and supporting said crystal element, and means also adjustably supported on said wave guide and supporting said point member solely at its end remote from the contact with said crystal element; said crystal supporting means and said point member supporting means including respectively to electrode members and sockets supporting said electrode members in a position adjustable in a direction perpendicular to said longitudinal axis, and at least one interchangeable conducting member and two insulating members; said conducting member being supported on one of said sockets outside thereof between said two insulating members to adjust terminal capacitance.

3. Crystal assembly of the asymmetrical conductivity type, comprising a wave guide corresponding to the frequencies utilized, a crystal element a surface of which is freely exposed to the waves guided by said wave guide, a flexible point member extending freely exposed to said waves and transversely of the longitudinal axis of said wave guide, said point member being in contact with the exposed surface of said crystal element, means adjustably supported on said wave guide and supporting said crystal element, and means also adjustably supported on said wave guide and supporting said point member solely at its end remote from the contact with said crystal element; said crystal supporting means and said point member supporting means including respectively two electrode members and sockets supporting said electrode members in a position adjustable in a direction perpendicular to said longitudinal axis, and a conducting member for each of said sockets and two insulating members; surrounding each of said sockets between said two insulating members and engaging a central portion thereof in replaceable position to permit 1 variation of terminal capacitance.

HERBERT FRANCOIS MATARE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,378,944 Ohl June 26, 1945 2,402,839 0111 June 25, 1946 2,432,116 McLean et a1. Dec. 9, 1947 2,438,521 Sharpless Mar. 30, 1948 2,460,109 Southworth Jan. 25, 1949 2,501,093 Raymond Mar. 21, 1950 2,563,613 Oh]. Aug. 7, 1951 said conducting member

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