AU651742B2 - Tunable microwave oscillator - Google Patents

Tunable microwave oscillator Download PDF

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Publication number
AU651742B2
AU651742B2 AU28575/92A AU2857592A AU651742B2 AU 651742 B2 AU651742 B2 AU 651742B2 AU 28575/92 A AU28575/92 A AU 28575/92A AU 2857592 A AU2857592 A AU 2857592A AU 651742 B2 AU651742 B2 AU 651742B2
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AU
Australia
Prior art keywords
terminal
resistor
coaxial resonator
radio
variable capacitance
Prior art date
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Ceased
Application number
AU28575/92A
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AU2857592A (en
Inventor
Holger Elias
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Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of AU2857592A publication Critical patent/AU2857592A/en
Application granted granted Critical
Publication of AU651742B2 publication Critical patent/AU651742B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • H01P7/04—Coaxial resonators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
    • H03B5/1805—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a coaxial resonator
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2200/00—Indexing scheme relating to details of oscillators covered by H03B
    • H03B2200/0014—Structural aspects of oscillators
    • H03B2200/002—Structural aspects of oscillators making use of ceramic material
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2201/00—Aspects of oscillators relating to varying the frequency of the oscillations
    • H03B2201/02—Varying the frequency of the oscillations by electronic means
    • H03B2201/0208—Varying the frequency of the oscillations by electronic means the means being an element with a variable capacitance, e.g. capacitance diode
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2201/00—Aspects of oscillators relating to varying the frequency of the oscillations
    • H03B2201/02—Varying the frequency of the oscillations by electronic means
    • H03B2201/0225—Varying the frequency of the oscillations by electronic means the means being associated with an element comprising distributed inductances and capacitances
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2202/00—Aspects of oscillators relating to reduction of undesired oscillations
    • H03B2202/03—Reduction of undesired oscillations originated from internal parasitic couplings, i.e. parasitic couplings within the oscillator itself
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2202/00—Aspects of oscillators relating to reduction of undesired oscillations
    • H03B2202/05—Reduction of undesired oscillations through filtering or through special resonator characteristics
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
    • H03B5/1864—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a dielectric resonator
    • H03B5/187—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a dielectric resonator the active element in the amplifier being a semiconductor device

Landscapes

  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)

Description

k 651742
AUSTRALIA
PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT
ORIGINAL
S F Ref: 219807 Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Siemens Aktiengesellschaft Wittelsbacherplatz 2 8000 Muenchen
GERMANY
Holger Elias Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Males, 2000, Australia Tunable Microwave Oscillator The following statement is a full description best method of performing it known to me/us:of this invention, including the 5845/5 -I Siemens Aktiengesellschaft Tunable microwave oscillator The invention relates to a tunable microwave oscillator according to the precharacterising clause of Claim 1.
Tunable microwave oscillators occasionally contain a ceramic coaxial resonator as the frequencydetermining component, as well as the variable capacitance diode to which a tuning voltage is applied.
Such ceramic coaxial resonators are dielectric components which are sintered and metallised in a tubular shape as round or rectangular rods with a suitable opening in the centre. If the metallisation is removed from one of the two ends, a coaxial line is obtained which is shortcircuited at the other end and has a very low impedance, and when used as a quarter-wavelength line, a resonator is obtained which has a high quality and very small dimensions in comparison with other line resonators.
As a result of the production scatters of the ceramic coaxial resonators and as a result of the tolerances of the other components of the oscillator, electronic tuning is necessary whose range, in the case of frequencies from two to three GHz should lie in the range from 20 to 30 MHz. For electronic tuning to the precise nominal frequency, the respective variable capacitance diode was until now connected for tuning purposes directly to the non-metallised ends of the coaxial resonator, for frequencies below 1 GHz. As the frequency increases, disturbing influences caused especially by the line inductances and capacitances increase i as a consequence of the mechanical dimensions of the construction. Moreover, as a result of the series resonance effect of the capacitance of the tuning diode with its terminal inductance, parasitic resonances also occur at frequencies above 1 GHz, as a result of which resonances the operation of the coaxial resonator is disturbed since undesired oscillation frequencies can occur in conjunction with the resonator circuit used. If the variable capacitance diode which is used for tuning 2 -2is connected to the base or collector terminal of the oscillator transistor, the output amplitude of the oscillator is considerably reduced, and if the variable capacitance diode is connected directly to the ceramic coaxial resonator, the result is a greatly restricted tuning range so that neither of the two possible variants results in any improvement in the operation of the oscillator at oscillation frequencies above 2 GHz.
The object of the present invention is thus to specify a microwave oscillator of the type mentioned initially which also operates in a stable manner at oscillation frequencies in the range from 2 to 3 GHz and has a sufficiently large tuning range.
The object is achieved according to the invention by means of an oscillator of the type mentioned initially, which is developed by the features specified in the characterising part of Patent Claim 1. The further patent claims describe preferred developments of the microwave oscillator according to the invention which are distinguished by a large possible capacitance change so that tolerances in the active circuit have only a secondary effect on the oscillation frequency, and even the use of cost-effective semiconductor components, that is to say of the variable capacitance diode and of the radiofrequency transistor used in the plastic housing, as well as the so-called MELF resistors, is possible instead of chip resistors.
The invention is intended to be explained in more detail in the following text on the basis of an exemplary embodiment shown in the drawing, in which: Fig. 1 shows the tunable microwave oscillator according to the invention and Fig. 2 shows a ceramic coaxial resonator included in Fig. 1.
Fig. 1 shows the tunable microwave oscillator which, as the active component, has a commercially available radio-frequency transistor T of the Type BFR 92, whose base terminal is connected via a first -3resistor R1 to a terminal UV for the base-bias voltage of an arrangement for operating point stabilisation ARBS.
In the connection between the first resistor R1 and the bias voltage terminal UV, a first capacitor C1 is connected to the reference potential and, in the connection from the first resistor R1 to the base terminal of the transistor T, a trimmer in the form of a so-called Gigatrim is connected to the reference potential. The frequency band in which a negative impedance is generated at the emitter terminal is also set for the Gigatrim tuning capacitor, whose capacitance and terminal inductance form a series circuit close to the oscillating frequency.
The collector terminal of the radio-frequency transistor T is connected via a coupling wire KD to the field of the ceramic coaxial resonator KKR, the inductances FK in this case representing the field coupling.
The emitter terminal of the radio-frequency transistor T is connected via the coupling wire KD to the one terminal of a variable capacitance diode CD and to the one terminal to a first inductance L1. The other terminal of *0 the variable capacitance diode CD is connected via a 0 second capacitor C2 to the reference potential and via a second resistor R2 to a terminal UAB for a tuning 25 voltage. The other terminal of the first inductance L1 is connected via a third capacitor T3 to the reference potential as well as to a terminal EV for the emitter current of the arrangement ARBS for operating point stabilisation.
The collector terminal of the radio-frequency i transistor T is connected via a second inductance L2 to ~the reference potential as well as via a pi-element, consisting of a third, fourth and fifth resistor R3, R4, to the output terminal AUS.
The arrangement for operating point stabilisation ARBS may comprise, as is shown in the exemplary embodiment, a voltage divider which contains a sixth resistor R6 whose one terminal is connected to a terminal Ub for -4the operating voltage and whose other terminal is connected to the one terminal of a seventh resistor R7 as well as to the terminal EV for the emitter current of the radio-frequency transistor T. The other terminal of the seventh resistor R7 is then connected to the terminal UV for the base-bias voltage of the radio-frequency transistor T as well as via an eighth resistor Rd to the reference potential. However, the arrangement for operating point stabilisation can also be constructed as a regulated power supply unit, which is monolithically integrated, in the case of very high stresses on the voltages and currents which are to be stabilised.
The ceramic coaxial resonator shown in Fig. 2 is produced from a commercially-available tubular body which is sinterei, is metallised on its inner and outer surfaces and has the external diameter D and the internal diameter d, in that the external metallisation AM has been removed at the rear end and a coupling wire which is approximately 1 mm thick is guided centrally through the opening in the tubular body and is held within the internal metallisation IM by a dielectric plastic piece o KS, the length L of the tubular body initially governing the frequency by its effect as a quarter-wavelength resonator for the oscillator.
The operation of the microwave oscillator according to the invention is based essentially on the fact that the variable capacitance diode for tuning is not connected directly to the ceramic coaxial resonator, for example to its external metallised surface or to the base i 30 or collector terminal of the radio-frequency transistor, but is connected to the coaxial resonator via a field coupling.
In this case, the coupling wire absorbs virtually the entire external field of the coaxial resonator, so that, close to the resonant frequency that is to say in the range from approximately 100 MHz around said frequency the new structure behaves virtually identically to the arrangement having a coaxial resonator with I 5 electrical contact being made in series with the inductance of the coupling wire. If this oscillator arrangement is now operated in the range from 60 to MHz above the quarter-wavelength resonance of a 2.5 GHz coaxial resonator, then a large capacitance change over the frequency is ensured, as in the past, without tolerances in the other components of the microwave oscillator exercising a significant influence on the oscillating frequency.
Downstream from the coaxial resonator, the coupling wire is connected to the series circuit which comprises the variable capacitance diode and the second capacitor C2 which linearises the frequency response, as well as to the second resistor R2 and to the first inductance LI. This results in an advantageous compact construction which, in addition to a small space requirement and short conductance paths, is insensitive to undesired couplings.
In addition to chip capacitors, the already mentioned MELF resistors were able to be used as passive components, which resistors comprise metal-layer resistors which are provided with caps without terminal wires, are suitable for radio frequencies and are comparatively cost-effective in comparison with chip resistors.

Claims (4)

1. Tunable microwave oscillator having a bipolar radio-frequency transistor, a ceramic coaxial resonator and a variable capacitance diode which is connected to one terminal of a tuning voltage, characterised in that the metallisation is removed at one end of the ceramic coaxial resonator (KKR) and a coupling wire (KD) which is connected directly to the emitter terminal of the RF transistor is- there-passed into the ceramic coaxial resonator (KKR) in that the coupling wire (KD) is connected at the other end of the ceramic coaxial reso- nator (KKR) to the variable capacitance diode (CD) and, via a first inductance (LI) to a source for the emitter current of the radio-frequency transistor in that a so-called Gigatrim capacitor is provided, whose one terminal is connected to the base terminal of the radio- frequency transistor and whose other terminal is connected to the reference potential, in that the collec- tor terminal of the radio-frequency transistor is connected via a second inductance (L2) to the reference potential and via a resistor pi-element to an output 0terminal (AUS), and in that the oscillating frequency of the oscillator is set slightly above the quarter- wavelength resonance of the ceramic coaxial resonator (KKR).
2. Tunable microwave oscillator according to Patent Claim 1, characterised in that the base terminal of the radio-frequency transistor is connected via a first resistor to a terminal (UV) for a base-bias voltage of an arrangement for operating point stabilisation (ARBS) and, additionally, via a first capacitor which is connected downstream from the first resistor to the reference potential.
3. Tunable microwave oscillator according to Patent Claim 1, characterised in that the terminal of the variable capacitance diode (CD) which is averted from the coupling wire (KD) is connected via a second capacitor (C2) to the reference potential and via a second resistor I (R2) to a terminal (UAB) for a tuning voltage.
4. Tunable microwave oscillator according to claim 1, characterised in that the collector terminal of the radio-frequency transistor is connected via a second inductance (L2) and a third resistor connected in parallel therewith, to the reference potential and, additionally, directly to a first terminal of a fourth resistor the other terminal of this resistor (R4) being connected via a fifth resistor (R5) to the reference potential and, additionally, to the output terminal (AUS). A tunable microwave oscillator substantially as described herein with reference to the drawings. Dated this Twenty-eighth Day of April 1994 Siemens Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON AND FERGUSON I I o 0 0 [n:\ibool00216:IAD w s -[n;\llboolO0216:lAD Abstract Tunable microwave oscillator Microwave oscillators which can be tuned by means of a variable capacitance diode often have, as the frequency-determining element for oscillating frequencies of a maximum of 1 GHz, a ceramic coaxial resonator, in which the metallisation is removed at one end and the variable capacitance diode is connected there. At fre- quencies above 1 GHz, that is to say especially at frequencies around 2.5 GHz, disturbing resonances occur and hence undesired oscillating frequencies, as a result of the series-resonant effect of the capacitance of the tuning diode with its terminal inductance, and as a result of the mechanical dimensions of the ceramic coaxial resonator. According to the invention, the emitter terminal of the oscillator transistor is there- fore connected via a coupling wire to the internal space of the ceramic coaxial resonator, and the variable capacitance diode is connected to the other end of the coupling wire. 0o Figure 1 A
AU28575/92A 1991-11-26 1992-11-24 Tunable microwave oscillator Ceased AU651742B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4138859 1991-11-26
DE4138859 1991-11-26

Publications (2)

Publication Number Publication Date
AU2857592A AU2857592A (en) 1993-05-27
AU651742B2 true AU651742B2 (en) 1994-07-28

Family

ID=6445618

Family Applications (1)

Application Number Title Priority Date Filing Date
AU28575/92A Ceased AU651742B2 (en) 1991-11-26 1992-11-24 Tunable microwave oscillator

Country Status (4)

Country Link
EP (1) EP0544180A1 (en)
AU (1) AU651742B2 (en)
FI (1) FI925350A (en)
NO (1) NO924553L (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2720879B1 (en) * 1994-06-03 1996-08-14 Gilles Morey Oscillator and receiver comprising this oscillator.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02284507A (en) * 1989-04-25 1990-11-21 Alps Electric Co Ltd Oscillator for radio communication equipment
JPH0336805A (en) * 1989-07-03 1991-02-18 Sharp Corp Oscillator
JPH03145808A (en) * 1989-11-01 1991-06-21 Maspro Denkoh Corp Microwave oscillator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02284507A (en) * 1989-04-25 1990-11-21 Alps Electric Co Ltd Oscillator for radio communication equipment
JPH0336805A (en) * 1989-07-03 1991-02-18 Sharp Corp Oscillator
JPH03145808A (en) * 1989-11-01 1991-06-21 Maspro Denkoh Corp Microwave oscillator

Also Published As

Publication number Publication date
FI925350A (en) 1993-05-27
NO924553L (en) 1993-05-27
FI925350A0 (en) 1992-11-25
AU2857592A (en) 1993-05-27
NO924553D0 (en) 1992-11-25
EP0544180A1 (en) 1993-06-02

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