High-frequency oscillator device, motion and / or presence sensor device, sensor system and use

Abstract

High-frequency oscillator device with a resonator section (10) provided on a printed circuit board and comprising a bipolar transistor (18) and ceramic resonator means (12), which is arranged for oscillator operation of the oscillator device at a fixed frequency, characterized in that the ceramic resonator means forming a first end of the resonator path on the circuit board are connected to the base (B) of the bipolar transistor via a matching line implemented as a first microstrip line (14), and the bipolar transistor is connected in such a way that in oscillator operation at the base there is a wave maximum of a superimposed forward (24) and backward (26) wave along the resonator path.

Description

[0001] The present invention relates to a high-frequency oscillator device according to the preamble of the main claim, a motion and / or presence sensor device according to the preamble of the dependent claim 7, a sensor system according to the preamble of the dependent claim 8 and a use of the high-frequency oscillator device according to the preamble of the dependent claim 10.

[0002] Such oscillator devices are generally known from the prior art and are used for a variety of applications.

[0003] US 4,445,097 discloses a microstrip transistor oscillator with stabilization by a dielectric resonator. The goal is to use a dielectric resonator with a very low temperature coefficient in a very high-frequency (3 to 10 GHz) transistor oscillator to benefit from both the high power available and the maximum frequency stabilization provided by the resonator. To this end, in a field-effect transistor, the gate is connected to a line separated from a dielectric resonator at a point on the line located at a quarter-wave. The end of the line opposite the transistor is connected to an open-circuit half-wave line via a discrete resistor. In this way, the oscillation is damped as soon as one deviates from the oscillation frequency to which the resonator is tuned.

[0004] US 5,473,287 discloses an improved limited-bandwidth electronic oscillator for better phase noise and linearity characteristics and a method of manufacturing it. A transmission line with specific characteristics is introduced between main components of the frequency source to significantly improve phase noise and linearity, and minor adjustments to the L / C ratio of the transmission line during production testing further optimize phase noise and linearity without adversely affecting other circuit parameters. The improvement primarily concerns the length, configuration, and accessibility of a transmission line connecting a resonator and a main tuning capacitor in a series resonant tank circuit of an oscillator.

[0005] DE 102 46 171 A1 discloses a high-frequency propagation time oscillator with a transistor component and a propagation time device associated with the transistor component, which is connected to effect feedback or positive feedback and which has no passive components, wherein the transistor component is mounted as an SMD component on an underlying printed circuit board and the propagation time device is designed as a power arrangement realized on the printed circuit board such that at least a section of the power arrangement runs on and / or in a region of the printed circuit board which is covered by the transistor component.

[0006] DE 20 2009 010 496 U1 discloses a sensor device for the motion-controlled activation of a light, comprising a high-frequency-based motion sensor which has a high-frequency resonant circuit for generating a high-frequency transmission signal, characterized by manually operable mechanical means which interact with the high-frequency resonant circuit for adjustably changing and / or detuning a resonant frequency of the high-frequency resonant circuit.

[0007] One example of the use of such oscillator devices is their use as a local oscillator for a motion and / or presence sensor device. In such a sensor device, which is again assumed to be known, the local oscillator signal generated by the oscillator device is used on the transmit and receive sides via appropriate mixer units to implement the sensor functionality. Such sensors typically operate according to the Doppler principle.

[0008] Particularly from the perspective of cost-effective mass production, it is known to provide a (generic) oscillator module and other high-frequency components on a printed circuit board, typically using microstrip technology. In conjunction with common oscillator topologies, such as an amplifying component with suitable feedback from a resonant circuit or a module with negative resistance behavior (present in a characteristic curve section) in the frequency range of interest, suitable oscillator modules can be realized for a specific application.

[0009] It is also assumed to be generally known from the prior art that a topology comprising a (high-frequency) bipolar transistor in a collector circuit, which provides a suitable frequency-determining component, e.g. a resonator element or a conductor path (as a microstrip line) suitably coupled to the bipolar transistor, this typically being done by means of a coupling capacitor or similar coupling capacitance.

[0010] While such oscillators exhibit fundamentally reliable oscillation behavior, which is also favorable for the "Doppler motion sensor" application, such indirect coupling (i.e., achieved via capacitance) poses the problem of sufficiently precisely determining or accurately determining the oscillation frequency. Due to their inherent design, component and manufacturing tolerances of the commonly used capacitor component have a significant impact on the oscillation frequency (hereinafter also referred to as the fundamental frequency or, since it is invariable, the fixed frequency), so that such conventional oscillator assemblies typically require trimming or calibration after production (e.g., by selectively removing surface area from a frequency-effective conductor section of the resonator path on the circuit board).However, this is particularly laborious and complex for large-scale production (since the actual vibration frequency usually has to be measured), so that there is a considerable need for improvement with regard to the effort and costs of large-scale production.

[0011] In the context of preferred uses of such oscillator devices as motion or presence sensors, the problem also arises that, for example, when using such motion or presence sensors for the motion-controlled activation of lights or similar electrical units, a plurality of sensors (which are then assigned either to individual associated lights or to a common lighting system for activation) are usually mounted on or in a detection area in such a way that mutual interference between neighboring motion or presence sensors cannot be completely avoided. In other words, a possible situation arises in which a high-frequency receiving part of a Doppler motion sensor receives not its own transmission signal, but the transmission signal of a neighboring sensor, thus resulting in unplanned detection states.

[0012] The state of the art provides solutions in this regard, for example, by equipping the respective sensors with (typically manually operable) trimmers or similar adjustment elements, which allow for the adjustment of sensors, particularly those located adjacent to each other, to non-identical fundamental frequencies. However, this approach requires specialist knowledge during setup and entails increased assembly and setup effort.

[0013] The object of the present invention is therefore to improve a generic high-frequency oscillator device, in particular for use as a local oscillator for a high-frequency motion and / or presence sensor, with regard to its manufacturing and production properties, in particular to ensure high reproducibility of a fundamental frequency (fixed frequency) of the oscillator with low dispersion within a manufactured series and, in particular, to make respective measuring and trimming of the manufactured oscillator devices (or the high-frequency assemblies realized therewith) obsolete. At the same time, the object of the present invention is to create a manufacturing-technically simple possibility that enables a variation of fundamental frequencies of a plurality of oscillator devices with little effort, with the aim of already during production and without the need for individual settings of a motion orPresence sensor at the site of use to avoid mutual (and undesirable) interference between neighboring or overlapping sensors in the respective detection area.

[0014] The object is achieved by the high-frequency oscillator device having the features of the main claim, and further by the realization of a motion or presence sensor device with a high-frequency oscillator device or by the use of such a device, wherein such a presence or motion sensor can in turn be advantageously used for the motion-controlled activation of electrical consumers, for example in the form of a sensor light. Furthermore, protection is claimed within the scope of the invention for a sensor system comprising a plurality of such motion or presence sensor devices according to the solution, wherein according to the solution the adjacent orSensor devices to be provided in an overlapping sensor detection area have respective high-frequency oscillator devices according to the invention, which, by varying a longitudinal extent of the respective microstrip lines for coupling the resonator means, have experienced a variation in the fundamental oscillation frequency in a manufacturing-technically favorable and reproducible manner (especially with regard to resonator components of one frequency).

[0015] In an advantageous manner according to the invention, it is first provided that the ceramic resonator means according to the invention are provided at a first end of the resonator section, which is more preferably configured to a length of 3 / 2 lambda of the fundamental frequency (fixed frequency). These resonator means, which are more preferably designed as a coaxial ceramic resonator within the scope of the invention, are advantageously connected to the base of the bipolar transistor via a matching line in the form of a microstrip line, so that a practically reflection- and loss-free high-frequency waveguide is created from the ceramic resonator to the transistor.

[0016] In the concrete implementation as a collector circuit, the resonator path runs from the base of the (high-frequency) bipolar transistor via the collector to a line section formed by the second microstrip line, which forms the second end (“radial line end”), so that an oscillator according to the invention can be realized using microstrip line technology and is therefore inexpensive to manufacture and suitable for large-scale production. At the same time, the ceramic resonator means provided according to the invention at the first end of the resonator path provide a twofold advantage compared to a (pure) stripline: Firstly, the ceramic coaxial resonator, which is used advantageously and in accordance with the further development, results in improved oscillator quality, and secondly, the provision of such ceramic resonator means enables effective spatial orGeometric shortening of the resonator section is achievable: At a fundamental frequency (fixed frequency) of 5.8 GHz with a wavelength of approximately 26 mm on the selected substrate, typical for the practical implementation of the present invention, a 1 / 2 lambda resonator section would require approximately 13 to 14 mm of microstrip conductor length. By using a coaxial ceramic resonator, this length is reduced to approximately 4 mm, with the resulting advantages of compactness of the oscillator device (and optimized influence through etching precision during production).

[0017] The matching line according to the invention thus creates the prerequisite for advantageously coupling the (ceramic) resonator means directly to the bipolar transistor, in particular without a coupling capacitor or coupling capacitance, thus eliminating the measurement and trimming effort associated with the component tolerances of conventional coupler capacitors. Rather, it has been advantageously found that highly reproducible oscillation characteristics (regarding the achieved fundamental or fixed frequency) can be achieved in the manner provided according to the invention, without the need for individual measurement and adjustment in series production.

[0018] This coupling according to the invention offers the additional advantage, according to a further development, of achieving a desired oscillation frequency variation of the high-frequency oscillator device in a technically simple manner, with the aim described above of being able to operate adjacent motion sensors or similar high-frequency units (each of which uses the high-frequency oscillator device according to the invention) in a mutual detection range without the risk of mutual interference. According to the invention, this is made possible by the fact that such reproducible frequency influence can be achieved merely by varying the length of the matching line (between the ceramic resonator means and the base of the bipolar transistor). In the typical application case of a fundamental frequency in the range of 5.8 GHz and the matching line set to a length of approximately 1 / 4 lambda (corresponding to approximatelyFor a microstrip line (7 mm in length, with a typical microstrip line width of approximately 0.13 mm), a length variation of this 7 mm section by + / - 0.2 mm, i.e., typically by approximately 2 to 4%, would be sufficient to generate a sufficient separation of the respective fundamental frequencies. At the same time, such variations do not have a critical effect on high-frequency matching or reflection behavior in this first end region of the resonator section.

[0019] The inventive provision of the ceramic resonator means (1 / 2 lambda), the matching line (1 / 4 lambda) and an adjoining microstrip line as a supply line (1 / 4 lambda) to the bipolar transistor, in conjunction with a 1 / 2 lambda line section to the second end of the resonator section, results in a total length of 3 / 2 lambda, which enables an overlapping wave maximum at the base of the bipolar transistor for forward and return waves (between the first and second ends). This, in turn, ensures that the transistor is driven. On the emitter side, part of the oscillation energy is coupled out for downstream aggregates and functional units, with the emitter of the bipolar transistor being connected to an impedance such that (non-coupled out) energy is reflected back into the resonator section and overlaps as above.

[0020] As a result, the present invention solves the underlying problem of significantly simplifying the large-scale production of high-frequency oscillator devices, particularly for use in motion or presence sensors, in a surprisingly simple and elegant manner, while increasing reproducibility in oscillation behavior and reducing scatter and virtually eliminating component-related tolerance effects. Accordingly, the present invention is advantageously suited as a local oscillator for the claimed use, but is nevertheless not limited to this intended use. Rather, it is suitable for any application of a high-frequency oscillator device in which these outlined advantages provide direct manufacturing and usage benefits.

[0021] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings, which show: Fig. 1: a schematic diagram to illustrate the structure of the resonator section according to the invention including amplifier semiconductor in the context of a preferred embodiment of the invention in the form of interacting functional components; Fig. 2: a circuit board layout representation of the embodiment of the Fig. 1 with arrangement and interconnection of the components used; Fig. 3: a realization of the Fig. 1, Fig. 2 corresponding circuit diagram and Fig. 4: a schematic diagram to illustrate the high frequency waveguiding in the implementation of the Fig. 2.

[0022] The Fig. Figure 1 shows a schematic view of the composition of the resonator section 10 from its functional components: At one end, and realized by a coaxial ceramic resonator (Q7) 12, a first section with a length of 0.5 x lambda is realized. A strip of microstrip line with a length of approximately 7 mm and a width of approximately 0.13 mm is connected to this as a matching line 14, thus realizing a length of 0.25 × lambda. A further, widened microstrip line section 16 (again with a length of 0.25 × lambda) is used to connect to the base of the bipolar transistor 18 (T7 in the circuit diagram), to which a stripline section 20 with an open line end (in the layout of the Fig. 2 fanned out) to create another line section of length 0.5 x Lambda. The enlarged view of the Fig. 2 transfers these schematic functional components to the circuit board layout, whereby the (high-frequency) bipolar transistor, shown in an SMD-capable package, has a double emitter terminal E1, E2 and (not shown in the figures) the (partial) coupling of the oscillator energy for downstream circuit components, such as transmitting and receiving side mixers, takes place at E1.

[0023] Clearly visible in the layout of the Fig. 2 that the microstrip lines 14, 16 are bent at right angles to each other, and it becomes clear that a further development-related lengthening or shortening of the matching line 14 with the purpose of a frequency variation in the circuit board production merely represents a (in the Fig. 2 then vertical) displacement of a resonator holder 22 for the coaxial resonator 12, preferably in the range of less than approximately 0.2 mm (the basis for all dimensional specifications is a fundamental frequency of 5.8 GHz).

[0024] While the formal circuit diagram of the Fig. 3 illustrates the circuit context of the collector circuit (without the microstrip line implementation in the Fig. 1, Fig. 2 are shown in detail), the schematic diagram of the Fig. 4 with arrows indicating the course of the forward and backward waves, the function and the vibration behavior of the embodiment of the Fig. 1 and Fig. 2. At the base of transistor 18, a forward wave (arrow 24) traveling from the coaxial resonator 12 via the line arrangement 14, 16 to the base is superimposed on a returning wave (arrow 26) reflected from the open strip end (of the stripline 20). A collector current flowing along the collector-emitter path is (partially) coupled out on the emitter side and partially reflected (arrow 28). A complex matching network 30 provided on the emitter side (in the Fig.1 to 3 not shown) is arranged so that the wave 28, with the wave maximum of the standing wave at base B or emitter E of the transistor 18, is reflected into the resonator section.

Claims

[1] High-frequency oscillator device with a resonator section (10) provided on a printed circuit board and comprising a bipolar transistor (18) and ceramic resonator means (12), which is arranged for oscillator operation of the oscillator device at a fixed frequency, characterized by , that the ceramic resonator means forming a first end of the resonator path on the circuit board are connected to the base (B) of the bipolar transistor via a matching line implemented as a first microstrip line (14), and the bipolar transistor is connected in such a way that in oscillator operation at the base there is a wave maximum of a superimposed forward (24) and backward (26) wave along the resonator path. [2] Device according to claim 1, characterized bythat the ceramic resonator means are connected directly and without a coupling capacitance, in particular without a coupling capacitor, to the base via the matching line. [3] Device according to claim 1 or 2, characterized by that the ceramic resonator means comprise a coaxial ceramic resonator (12, Q7) which is provided at the end of the matching line on the printed circuit board. [4] Device according to one of claims 1 to 3, characterized by that the resonator section is set to a high-frequency effective length of 3 / 2 or an integer multiple of half the wavelength of the fixed frequency. [5] Device according to one of claims 1 to 4, characterized byin that, to form a second end of the resonator section, a line section designed as a second microstrip line (20) with a high-frequency effective length of 1 / 2 the wavelength of the fixed frequency is connected to the collector (K) of the bipolar transistor. [6] Device according to one of claims 1 to 5, characterized by that an oscillator output signal of the oscillator device is coupled out via the emitter (E) of the bipolar transistor, preferably via a coupling capacitance. [7] Motion and / or presence sensor device, comprising the high-frequency oscillator device according to one of claims 1 to 6, in particular as a local oscillator of the sensor device realized according to the Doppler principle. [8] Sensor system comprising a plurality of the motion or presence sensor devices according to claim 7, which are arranged and / or provided for operation within a mutual sensor detection range, characterized by that the matching line of the high-frequency oscillator device of a first of the motion or presence sensor devices, which is implemented as a first microstrip line, has a length which differs from the length of the matching line of a second of the motion or presence sensor devices, which is implemented as a first microstrip line. [9] System according to claim 8, characterized bythat the length difference is less than 4%, preferably less than 2%, based on the greatest length of the microstrip lines and / or the differing lengths are set to a range between 0.96 × Lambda / 4 and 1.04 x Lambda / 4, where Lambda is the wavelength of a mean of the fixed frequencies of the respective high-frequency oscillator devices. [10] Use of the high-frequency oscillator device according to one of claims 1 to 6 for realizing a presence and / or motion sensor for persons for activating an electrical consumer, in particular an electrical lighting device.

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