DE1616343A1 - Tunable, single-stage semiconductor multiplier with a large multiplication factor - Google Patents

Description

IJi η ypm ^ BIT

Patentverwertungsgesellschaft m.b.H. ος / 67-BK

Tunable, single stage semiconductor multiplier with large

Multiplication factor

The invention is concerned with a tunable, single stage Semiconductor multiplier with a large multiplication factor (n> 10) for signals in the GHz range using a waveguide Semiconductor diode with a rectangular cross-section, which transmits the signal to be multiplied via a matching network is supplied coaxially, and to reduce the conversion losses is trotiiaal adapted to the output.

A semiconductor diode can be doped so that it is suitable for a short defined time in the reverse direction is just as conductive as in the forward direction. This effect is due to its presence remaining minority carriers that were stored in the flow direction during the previous operation. the Reverse conductivity resulting from storage is detrimental for many applications, in one specific one However, this type of diode is consciously exploited. These diodes are known as "step recovery diodes" or switching memory diodes become known "

By properly.-Wan of the doping profile, it is possible to influence the storage time and the switch-off target. The jump in current when switching off can be used to narrow

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To generate pulses or, viewed in terms of frequency, a broad spectrum of harmonics up to the GHz range. Such diodes are used today in many different circuit arrangements for single-stage frequency multiplication with high multiplication factors.

Basically one assumes that one is in a generator a frequency fo generated, for example 500 MHz should * The generator is connected to the step recovery diode via a matching network, which is used to transform the wave impedance of the generator to the wave impedance of the step recovery diode at fo. The step recovery diode follows then a resonance circuit which is tuned to the desired harmonic, for example the tenth harmonic, that is to say to 5000 MHz is. This resonance circuit is followed by the consumer to which the power is delivered at the multiplied frequency.

The resonance circuit is directly coupled to the diode. A pulse generated by the step recovery diode triggers the resonance circuit directly and it swings out in a damped manner. The damping of the circle consists on the one hand of its own losses and, on the other hand, from the payload. The pulse generation by a step recovery diode is easy From an equivalent circuit diagram. In Fig. 1 of the drawing in a generator G, the oscillation of the frequency fo generated. The generator drives the step recovery diode D via an inductance L, which acts as a pure switch. It is

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there are two operating states:

Positive half-cell «fez * generator voltage:

a) It flows in. Current i through the inductance L and the step recovery diode D "represented by a low resistance R (see Fig. 2). A magnetic field builds up in the inductance L.

Negative half-wave of the generator voltage:

b) The polarity of the voltage has changed. The load carriers are sucked out of the doping zone. The step recovery diode D has switched off. She acts like one now Capacity C (see Fig. 2). The magnetic energy stored in the inductance L causes a steep increase in voltage above the switch, in this case above the step recovery diode.

FIG. K shows the voltage profile across the step recovery diode and FIG. 5 shows the corresponding image of the current profile through the step recovery diode D. The abrupt breakdown of the diode current can be clearly seen. The resonance circuit, which is tuned to the desired harmonic, is triggered by a voltage pulse according to FIG. 4. It then swings out in a damped manner by simultaneously providing the consumer with the useful power in the form of a damped oscillation

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Frequency (n. Fo) emits "

Ee are known from the German Auslegeschriften 1 2kB 737 and 1 248 738 multipliers, which also suggest the use of semiconductor diodes. These semiconductor diodes are arranged in a waveguide, the height of which is adapted to the size of these diodes The fixed assignment of the diode in the waveguide means that this multiplier cannot be used for large frequency ranges, in particular Af = + ^ 10? 6 of the center frequency with maximum efficiency and temperature constancy over a range of almost 80 C with a multiplication factor of η ^ 15. In order to meet these requirements, it is necessary to provide additional compensation elements that implement the transformations to the given wave resistances, combined with the suppression of the undesired harmonics that occur.

The object is achieved by the invention characterized in claim 1 solved.

The invention is explained in more detail using an example with the aid of the drawing described. In FIG. 6, the basic circuit diagram of the arrangement according to the invention is reproduced, while FIG. 7 shows the

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represents the schematic structure of this arrangement.

The basic circuit diagram shown in FIG. 6 shows a generator G which is connected via an input E _{1 to} a circulator Z * with a network N which contains capacitors C1, 2, C5 and inductances L1 and L2. The connection to a diode D, the multiplier diode, is established via a λ / k line. The diode D is directly connected to Nasse from the same terminal via a choke Dr and a resistor R. A tunable line X2 and a line length a and a filter F via which the multiplied signal is fed to output A are also connected from here in terms of circuitry. The second terminal of the diode D is connected to ground via a dummy line Xl

The mode of operation of this arrangement according to FIGS. 6 and 7 is as follows: A signal voltage of the fundamental frequency fo is generated in the generator G and the input terminal E of the multiplier arrangement with the network N serving for adaptation to the diode D via a network N acting as an isolator Circulator Z ¹ supplied. The circulator Z ', one of which is terminated with the characteristic impedance Z, thus acts as a pure insulator L2, delivered to the λ / 4 line located at the output of the network N. Omr, the circulator Z 'acting as an isolator prevents reflection

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dor transformation elements of the network N in the direction of the generator G. The aim of the compensator is that the diode D sees its effective characteristic impedance in the direction of the input. In order to prevent the energy components of the desired harmonic from flowing back into the network N, an XA line is inserted between diode D and the network N, the length t / k of which is the wavelength of the harmonic used and thus represents a high-impedance termination for the useful frequency «

The decisive factor for the lowest conversion losses in the case of multiplication is not only the adaptation of the diode D in the input, but also the adaptation to the output. The variable dummy lines Xl and X2 are used for this purpose Dummy line Xl arranged as a variable coaxial line in the axial direction to the diode D and the dummy line X2 as Short-circuit slide are formed in the waveguide. These two dummy lines X1 and X2 result in an optimal adaptation achieved to the following broadband filter. A special The advantage of these variable line lengths is to be found in the fact that their slide can be brought up to the diode D so that the transformation paths are short and the transformations are broadband. This affects especially favorably on the electrical stability of the multiplier. The connected line length a serves to suppress undesired harmonics.

Since »Problem of suppressing unwanted harmonics 95/67-ΒΪ 109815/0247" ⁷ "

is in the foreground of this entire arrangement. The following measurements are decisive for this: The mentioned connected line length a between diode 0 and the filter F, the cutoff wavelength XGr of the waveguide H, which is determined by the width of the waveguide. Furthermore, the λ / 4 line is dimensioned for the useful frequency so that all undesired harmonics can run back into the input network N. The filter F following the multiplier is dimensioned in such a way that its blocking range is effective for the adjacent harmonics.

It is particularly advantageous if the one facing away from the energy supply To connect the diode terminal to ground via a coaxial short-circuit slide (Xl).

Furthermore, a further development of the invention consists in the diode D supply a separate DC voltage in order to influence the operating point of the diode D. In this way it is possible to Diode D imposes a certain operating point that influences the output power. Switches under normal conditions one the diode D via a choke Dr and a resistor R direct current to ground, so that the due to the Diode D applied AC voltage generated voltage drop, causes an automatic pre-tensioning. To improve the temperature independence in a wider range, it is

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it must be necessary to assign temperature-compensating properties to the resistor R

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Claims (9)

T6W343 patent claims 1) Tunable, single-stage semiconductor multiplier «it large multiplication factor (n> 10) for signals in the GHz range using one in a waveguide with a rectangular Cross-section arranged semiconductor diode, which the signal to be multiplied via a matching network coaxially is supplied, and to reduce the conversion losses is optimally adapted to the output, characterized by the simultaneous use of the following features, some of which are known per se: a) 0er waveguide (H) points in the output of the multiplier arrangement facing away from a short-circuit slide (X2). b) The inner conductor of the coaxial line serving to supply energy to a diode terminal is reinforced so that it represents a capacitance in the supply line and a high-value resistance (λ / 4 line) for the multiplied signal. c) By a line length (a), or another Traneformations circuit, becomes the singing resistance of the filter (F) for the frequencies adjacent to the output frequency transformed in such a way that an open circuit appears in the diode level * 95/67-BK 1098 15/0247 -IG- 2) semiconductor multiplier according to claim 1, characterized in that that the signal to be multiplied via a matching network (N) is supplied because in the technology of the printed circuits is made. 3) Semiconductor multiplier according to claim 1, characterized in that the matching network (N) is preceded by a circulator (Z ¹ ) connected as an isolator. k) semiconductor multiplier according to claim 1, characterized in that the multiplier is followed by a bandpass filter (F), the lower plank of which has the highest multiplied frequency of the (n »fo-l) th harmonic and the upper plank of which the lowest multiplied frequency of the (n .fo-tl) -th harmonic still block " 5) semiconductor multiplier according to claim 1, characterized in that that the 4-way waveguide (H) is so dimensioned in its width is that its cutoff frequency is higher than the (n.fo-l) -th Harmonic lies " 6) semiconductor multiplier according to claim 1, characterized in that that the diode (D) has a separate fixed DC bias receives. 7) semiconductor multiplier according to claim 1, characterized in that that the diode (D) is connected to a * resistor (R) 95/67-BK - 11 - 109815/0247 -U- decreasing automatic preload receives 8) semiconductor multiplier according to claim 7 *, characterized in that that the resistor (R) producing the automatic bias has temperature-compensating properties. 9) semiconductor multiplier according to claim 1, characterized in that that the diode terminal facing away from the energy supply is connected via a coaxial short-circuit slide (Xl) Ground is laid. 95/67-BK 109815/0247