WO2006050705A1

WO2006050705A1 - Resonator system and method for increasing the load quality of a resonant circuit

Info

Publication number: WO2006050705A1
Application number: PCT/DE2005/002011
Authority: WO
Inventors: Holger Heuermann
Original assignee: Fachhochschule Aachen
Priority date: 2004-11-10
Filing date: 2005-11-09
Publication date: 2006-05-18
Also published as: DE102004054443A1

Abstract

The invention relates to the design of common-mode operated and push-pull operated resonators. Disclosed are both transmission resonators and reflection resonators that are based on series or parallel resonant circuits. Said dual-mode resonators can be produced with any previously known resonator for TEM modes and quasi-TEM modes, e.g. quartzes, dielectric resonators, LC resonant circuits, SAW and BAW resonators, coaxial line resonators, and many more. The dual-mode operation provides said resonators with a quality that is improved by a factor of 2 compared to the quality obtained during classical operation, resulting in phase jitter being reduced by 6dB on a broadband level when said resonators are used in oscillators, for example. In clock oscillators, jitter can thus be reduced by one order of magnitude. Transmission losses in resonator-based filters are also reduced by about 30 percent. The required circuitry effort is so small compared to the classical use of resonators that one can expect this new concept to be used in many new products as a result of the improved electrical properties.

Description

Resonator system and method for increasing the loaded quality of a resonant circuit

[0I] In electronics, which can be considered as an electro-technical field up to frequencies of a few MHz, the term resonator is somewhat unusual, although there are also a number of applications in this frequency range whose electrical quality depends on the quality of the resonators used (often referred to as resonant circuits) depends. A very good basic description of the state of resonators is given in the book by W, Bächthold entitled "Microwave Technology", published by Vieweg, Braunschweig, 1999.

[02] All resonators show the behavior of a series resonant circuit (absorption circuit) or parallel resonant circuit (blocking circuit) with an equivalent circuit consisting of inductivity, capacitance and a loss resistance (Figure 1). In this case, L and C are assumed to be ideal and all losses are combined in the resistor R. These core elements of the Ersatz¬ circuit diagram describe the essential properties of the resonator and from them all important characteristics can be derived.

[03] The resonance frequency of the resonant circuit is thus:

[04] Due to the ever-present losses, the amplitude of a free oscillation triggered only once will decay exponentially. In the case of a forced, externally excited oscillation, these losses spread the resonance curve.

[05] The quality factor is defined as a measure of the losses: stored energy

Qo = 2π

Energy losses per period

[06] The electrical quality of the resonator is directly dependent on this ratio. In the development of resonators, efforts are therefore being made to realize the highest possible quality factors and to then optimize the available technologies. This as well as lower manufacturing costs have hitherto always been the goals in the development of improved resonators. [07] An oscillator consists of a amplifying element (general amplifier) and a feedback element, which identifies a frequency-selective positive feedback. The latter is realized with frequency-stable oscillators by means of a resonator and an optionally necessary coupling circuit.

[08] Since frequency is directly proportional to time, electronics in electronics use oscillators in watches and controls, such as CD and DVD players, as well as computers. For such use cases a best possible frequency stability is required. The oscillators required in these applications are generally referred to as clock oscillators. Only by improving the frequency stability can the write / read speed and possibly the storage capacity of optical data carriers (CD, DVD) be increased. Poor frequency stability is often referred to as gating in electronics and broadband digital and broadband transmission technology. Reducing the lattice allows larger amounts of data to be transferred without degrading the so-called bit error rates. Similarly, a reduced grid is necessary if you want to increase the clock frequency and thus the processing speed of a computer.

[09] In radio transmission technology, all systems are now stabilized by so-called PLL circuits in the frequency position and the "purity" of the signals (the phase noise) A PLL uses a quartz oscillator and a high-frequency oscillator, which always has an RF resonator The phase noise of both oscillators is incorporated in the overall quality of the circuit. In modern RF transmission systems, it is no longer the self-noise of the receiver but the phase noise of the oscillators which limits the transmission quality.

[10] A very important component in all systems of transmission, measurement and control technology is the filter circuit, which essentially fulfills the following tasks:

- band limitation,

- frequency selection,

- interference suppression, - broadband adaptation

and resistance transformation.

[H] For the time- and value-continuous signals available in high-frequency technology, primarily analog, passive filters are used. That is, these signal filters are still realized in circuit technology. The electrical properties of filter circuits generally have a linear proportionality with the electrical properties of the entire system and thus directly influence important system features such as the signal / noise ratio, signal integrity or the bit error rate (BER for short) ) in digital circuits. Since there are electrical circuits, The aim is to refine the art of designing and implementing filter circuits with good properties. An indication of this is the proportion of publications on filter circuits in technical journals for electrical engineering.

[12] In recent years, attempts have been made to improve the properties of filter circuits by expensive improvements of the elemental qualities, namely the capacitances and inductances. In the course of such research, ceramic carrier materials with negligibly small dielectric losses, such as in "Low Temperature Co-fired Ceramics" (LTCC), or semiconductor manufacturing technologies for multilayer circuits have been developed for mass production, and bandpass filters are often required in these modern production technologies as well. For the realization of the band-pass filters, almost exclusively topologies are used which use resonators.When the qualities of the resonators are improved, the transmission losses of the filters are reduced.A reduction of the transmission losses allows the RF transmission power in the transmission path and reduces the noise figure in the receive path, In addition, filters with reduced losses have a higher selectivity.

Therefore, in recent years and decades, great efforts have been made in the realization of highly integrated and cost-effective resonators with the best electrical quality. Modern communication systems would not be conceivable without highly selective filters based on SAW or BAW resonators. With every new standard, the demands on the bandpass filters are increasing. A typical example is the comparison of the receivers requirements for a GSM system with the requirements for a duplexer for UMTS.

[14] The known resonator types are predominantly used in classical, asymmetrical TEM two-conductor systems. Here, only the unbalanced mode is capable of propagation, which is in close proportion to the so-called common mode of a three-conductor system. The two conductors of the two-wire system are divided into signal conductors and ground or forward and return conductors. The occurrence of further vibration modes is not possible in this case and the resonator thus operates in a so-called mono-mode operation. A typical two-wire system in modern high-frequency electronics is the microstrip line.

In contrast, modern high-frequency systems are increasingly being laid out in symmetrical line technology. In addition to improving the immunity to external radiation, the achievable output power can be multiplied here. In a purely symmetrical two-wire system, only the push-pull mode is capable of propagation, that is to say, against ground, a signal which differs only in sign is measured on both conductors. In practice, a two-wire system usually becomes a three-wire system, since almost always a ground plane, either on the board or due to a housing wall, must be taken into account. Now, as shown in Figure 2, two different TEM waves can propagate. DC and push-pull modes occur together here. In the field of high-frequency electronics, two purely ground-coupled microstrip lines are used.

[17] The description of mixed-mode systems (Figure 3), i. Systems in which more than one mode is capable of propagation is carried out, as in asymmetrical systems, by linking the wave quantities entering and leaving the gates.

[18] In mono-mode systems, these ratios are recorded in the known scatter or S matrix. The equivalent of the mixed-mode case (MM case for short) results in the M-matrix. It has the following form:

[19] The four quadrants each have a function comparable to scattering parameters of an unbalanced two-port.

M = M _n M ^~ ₂

Reflection and transmission of the MM two-port for the push-pull

M 21 ^M 22Λ

Reflection and transmission of the MM two-port for the common mode

Reflection and transmission of a common mode in Gegentakt konvertier¬

th wave

M = M _n - Mt ₂ - Reflection and transmission of a push-pull converted into common mode

mi; M ₂ _V. th wave [20] Through complex improvements of the manufacturing technology is trying to realize circuits with better electrical properties. In order to achieve an increase in the quality factor of a resonator, an improvement or the change of the underlying technology has been sought so far. The latter trend is exemplified by the BAW filters, which show an improved performance in terms of quality improvement and higher performance compared to the SAW filters.

[2I] There have been no clear innovations in questions of conceptual system design and circuit technology. An improvement of the underlying topology and operation of resonators is not followed so far.

[22] Although there are constant improvements in optimizing the circuit design of oscillators. But all the known approaches use only classical resonators. Meanwhile, in RF communication technology, the push-push oscillator (also differential oscillator, Figure 11), in particular for integrated solutions in CMOS, should be regarded as the standard. Although this is clearly a mixed-mode system in the usual realization on a semiconductor, there is no analysis of this circuit in parameters, which forms the basis for the innovation step presented in this patent.

[23] For quasi-transversal electromagnetic (TEM) conductors, such as the microstrip, coplanar, triplate, or coaxial, which form the basis of modern mass communication, there are some known filter circuits with dielectric resonators, LC resonant circuits, and SAW or BAW resonators. Figure 13 shows a simplest filter with coupled resonators. There is no known filter for this TEM ladder that supports the propagation of multiple modes within the resonators. Conceptual approaches for the exploitation of the two propagatable modes on such three-conductor systems have not been presented in specialist publications.

It is therefore an object of the present invention to provide a resonator system and a method for increasing the loaded quality of a resonant circuit, which show improvements in their characteristics due to a changed topology and operation over the prior art.

As a solution, a resonator system comprising a coupling network, at least one fashion blocker, at least one resonator and at least one mode converter, which are connected to one another via a multi-conductor system having at least two signal conductors and a ground, is proposed, wherein the

Resonator has a resonant frequency and in the resonator at least two modes of the resonant frequency resonant circuit wave are capable of propagation, wherein the mode blocker is arranged between the resonator and the coupling network or in the coupling network and one of the two modi not leave the resonator system and wherein the mode converter a first in the mode converter incoming mode of the two modes in the other mode the two modes transferred.

Furthermore, as a solution, a method is proposed for increasing the loaded quality of a resonant circuit, in which a first mode of a resonant circuit wave propagatable in a resonator system of the resonant circuit is excited via a coupling network, passed through a resonator of the resonator system and into another mode thereof Resonant circuit wave is converted, which mode is then also passed through the resonator, without leaving the resonator system completely, and then converted back into the first mode.

Preferably, the further mode passes through the resonator twice before its back conversion, whereby a better yield and thus improved quality of the resonator can be ensured.

[28] Also, it is accordingly advantageous if at least one mode is reflected during the conversion.

[29] The solutions listed above are not to be confused with the publications of HEUERMANN, Holger, et al. "A Synthesis Technique for Mono- and Mixed-Mode Symmetrical Filters" in 34th European Microwave Conference, 2004, Oct. 11-15, pp. 309-312 and "31ocking Structures for Mixed-Mode Systems" in the 34th European Microwave Conference, 2004, Oct. 11-15, pp. 297-300, both of which present novel representations of filters and fashion blockers that are optimized for use in dual-mode systems, that is, these new components filter one mode or completely transmit and suppress the other mode as much as possible. According to the invention, however, for the first time two modes are constructively used in one and the same circuit unit. Furthermore, of course, a resonator circuit differs from a bandpass filter or a fashion blocker. Although fashion blockers can be used as sub-component in a resonator system according to the invention, they do not characterize it. With regard to the filters mentioned in the above publications, resonators are coupled to one another, as is very often the case in high-frequency technology. However, these were classic mono-mode LC resonant circuits.

Modern gates of the digital circuits can be used without error at switching frequencies of well over 6GHz. To reliably perform the logic functions at high clock rates It is already state of the art that the gates are triggered by a so-called clock signal. The cut-off frequencies up to which these circuits can be operated depend essentially on the availability of a "pure" clock signal, which clock signal is generated in the clock generator Clock generators while maintaining the quartz crystals used so far zentra¬ le resonator elements by orders of magnitude "pure" clock signals generate. If one converts the "lattice" into phase noise, it can be said from previously performed nonlinear oscillator simulations and measurements that the phase noise is reduced by 6 dB .These improved clock generators form the basis for a further increase in the performance of the computers within the microprocessor, as well as the data transfer rates over the internal buses to the other peripherals, which can also be improved with this concept:

The access times of hard disks and CD / DVD devices can be reduced.

Increase the storage capacity of hard drives and CD / DVD devices.

Graphics cards can be clocked higher. - The power consumption of all CMOS circuits and thus the entire computer can be noticeably reduced at high clock rates.

[31] A substantial part of broadband communication for large amounts of data is covered by glass fiber technology. With this technology, which now transmits data rates in the double-digit Gbit range over one fiber, the limitation is the production of the electronic coupling and decoupling circuits. These data rates can also be appreciably increased if more precise clock generators are available, which is made possible by the present invention.

In all radiofrequency radio transmission systems that rely on effective utilization of limited frequency bands, it is highly interesting to use improved resonator systems for filtering and signal generation.

[33] A further increase in parameters such as phase noise and edge steepness of the transmission components mean a higher selectivity for all known transmission standards and thus offers the option of transmitting over longer distances or reducing the transmission powers. The results so far permit the estimation that the transmission power can be reduced to less than a quarter of the previous power while the transmission quality remains the same. Thus, on the one hand, the operating time of mobile devices could be extended by a factor of about 4 and, on the other hand, the high-frequency radiation load on the environment could be reduced by the same factor 4. [34] The presented concept enables this clear improvement of the system performance with minimum effort. Due to a very small change in the existing topology, a widely arbitrary resonator can be exploited several times in different vibration modes. The system will run once in push-pull and common mode. The quality of the optimized resonators is improved by a factor of 2. For use in oscillators and VCOs, this means an improvement in phase noise by 6 dB compared to conventional differential systems. Novel multi-mode filters for TEM conductors based on the present invention would allow the construction of a new generation of filters which, according to the current knowledge of the patent applicants, have steeper edges at a very low overhead,

- reduce the transmission loss by about 30%,

- or generate additional zeros in transmission path.

[35] The idea of using a resonator system beyond the fundamental mode can be extended arbitrarily by a dual-mode system. In general, with the availability of suitable mode converters and coupling elements, an n-mode system could be realized. Even with a four-wire system, the number of modes could be doubled to 4, which will probably lead to a further 6 dB improvement in phase noise.

[36] In particular, a three-conductor system can be provided internally, consisting of two signal conductors and a ground, in which only TEM waves, which are referred to as DC and push-pull mode, are capable of propagation, and with one or more resonator elements, the physical Realization form and manufacturing technology are arbitrary, which makes it possible that between two electrical terminals, a series or a parallel resonance occurs at the resonant frequency fö, Here can a. either a resonator element or a plurality of identical resonator elements between the signal conductors and / or be connected by a signal conductor to ground, having either a series or a parallel resonance, or n * 2 (n = l, 2, 3, ...) identical resonators elements having either series or parallel resonance, connected in series or crossed to the signal conductors, b. one or two mode converters are connected in series with the resonator element or the resonator elements, or a mode converter is already connected under a. has been implemented, which converts a push-pull mode from a DC mode and vice versa as a reflected signal and, if necessary, transmits a small part of the signal, and c. a coupling network or the coupling circuit can transmit a mode entirely or in part by the resonator system to one or more symmetrical or asymmetrical gates and lock the other mode.

[37] Even systems that behave like a resonator can benefit from multi-mode operation. Thus, the use of the concept is also conceivable for an antenna, which is also in resonance at transmission frequency. Since the antenna structure is now passed through twice (as will be shown below), it can radiate twice and is therefore at least better adapted. Consequently, the antenna transmits more energy into the free space. Of course, the radiation characteristic of the antenna is influenced by the MM operation. This would result in new degrees of freedom for the development of pivotable antennas as well as umpolarisierbaren antennas.

[38] In the realization of digital filters one likes to resort to classical filter synthesis for the production of passive filters. The reason is that these designs are always stable. The new methods presented here for the improved realization of resonators provide improved selection properties without increasing the number of resonators. Consequently, these can also be used for improved digital filters.

[39] A new concept for the realization of a resonator system was developed, in which the two modes of vibration DC and push-pull are used together to increase the performance.

[40] In particular, the resonator system can be designed as a reflection resonator and can comprise a frequency-selective mode converter with one or more resonator elements, where a. Either the mode converter of one or more parallel parallel resonators which are connected to a signal line and to ground, and an open circuit of the other signal line and thus only the incident signal at the resonant frequency is reflected as a converted signal b. or the mode converter of one or more series-connected series resonators, which are connected to a signal line and to ground, and a short circuit of the an¬ their signal line and thus only the incident signal at the resonant frequency is reflected as a converted signal c. or the mode converter comprising one or more parallel resonators connected in parallel and connected to one signal line and ground, and one or more series resonators connected to the other signal line and to ground are switched, and thus only the incident signal is reflected at the resonant frequency as kon¬ vertiertes signal.

[41] Preferably, the resonator system has a resonant frequency fθ and is designed as a reflection and / or transmission resonator, wherein a. the mode converter consists either of a small grounded inductance and a small series capacitance, or of a large series inductance and a large grounded capacitance, each introduced in a series line, and b. the mode converter consists of a series resonator and a parallel resonator whose resonant frequency deviates from fθ in such a way that at fθ the reactive elements under a. result.

[42] In a preferred embodiment, the resonator system can be realized as a pure reflection resonator, the mode converter consisting of a short circuit at one end of the line and an idling at the other end of the line.

[43] Also, the resonator system may be formed as a resonance component, which is introduced into a two-wire or two-wire system, wherein a. the coupling network for use as a reflection resonator consists of two identical coupling elements for unilateral coupling or decoupling from the signal conductor of the two-wire system via the Gleich¬ clock mode on the three-wire system and the push-pull mode is reflected, or b. the coupling network for use as a transmission resonator of two identical

Coupling elements for two-sided coupling and decoupling from the signal conductor of the two-wire system via the common mode to the three-wire system and the push-pull mode is reflected.

[44] The coupling network preferably comprises low-loss coupling elements, in particular at least one small capacitor and / or at least one large inductance.

[45] The basic concept of the dual-mode resonator system for use as a reflection circuit is shown in Figure 4. Figure 5 shows the new resonator system for the transmission insert. In the following, the system elements will first be described in detail. Thereafter, the appli cation for oscillators and filters will be described.

[46] The general system is divided into the three blocks coupling network, resonator and mode converter. [47] The coupling network 41 or 51 is the connection between a two- or three-wire system with the three-conductor system of the dual-mode resonator. In the simplest case you can couple two three-wire systems through the direct connection "hard", in which case no component is needed to implement the coupling network, but the subsequent circuit must have the mode blocking function The degree of coupling can be determined via the type and design of the network .As a rule, a weak coupling, for example via a capacitive voltage divider, can be determined by means of an internal resonator system (consisting of resonator 42, 52 and mode converter 43, 53). In practice, the coupling network is used to perform an impedance transformation If the resonator is based on a parallel resonant circuit, then the impedance is transformed high Series resonant circuit, then the impedance is transformed to a low-ohmic value. This measure allows greater selectivity.

[48] For the achievement of the system performance, a mode selection by the coupling network is required. So it is possible that only one mode can be coupled into the resonator system and only this mode leaves it again. Internally, the resonator system can then be repeated through a two-fold mode conversion.

[49] A mode-blocker structure can be chosen which, for example, couples a push-pull in the desired degree but reflects the common mode. These properties would e.g. met by a transformer. Alternatively, it is also possible to use resonant circuits connected to ground, which fulfill the functionality of the impedance transformation and of the mode blocker. An example is shown in Figure 9, which is discussed in the following section.

[50] For the opposite case, that a transmission of the common mode into the resonator system is desired, but the push-pull should be blocked, the coupling network can also have only one common connection for both paths. For a push-pull signal, this short circuit represents a biking structure. It is completely reflected.

[51] This common-mode coupling is advantageous for unbalanced circuits in which a "classic" resonator is to be replaced If the "classical" resonator was coupled in and out via an SMD component (coil or capacitor), then In the case of the dual-mode resonator, two identical SMD components are now required in each case. In contrast, if the "classic" resonator has been coupled in and out via an SMD component (coil or capacitor), then two identical SMD components are required in the case of the dual-mode resonator, examples of which are shown in FIGS and FIG. 14, which will be discussed further below. [52] The resonator 42 or 52 used is independent of the technology and it is fundamentally possible to use all known implementation methods which were previously also used in electrical circuits and operated via mono-mode TEM or quasi-TEM lines were. However, the design must ensure that the frequency-selective mode of action is given for both desired modes.

In the substitute pictures, an LC resonator is used in the following uniformly, but can be generalized according to the above condition.

[54] At the mode converter 43 or 53, a reflection of the DC and push-pull wave and Kon¬ conversion of the modes takes place. An incident common mode wave is converted into a push-pull wave, and vice versa. In the case of the converters presented below, the conversion acts on the reflected portion of the wave, by implementing different reflection factors for the two paths. Mode converter concepts with low transmission can be very useful for decoupling.

[55] The invention is based on the basic knowledge that a resonator of this system can be used several times by a mode conversion in a resonant circuit system comprising a multi-conductor system, and in this way the loaded quality of the resonant circuit can be considerably increased. Accordingly, this arrangement corresponds to the unrealizable attempt to couple two or more resonators directly in order to improve the loaded quality, which in reality can not lead to satisfactory results since completely identical resonators would be required for this purpose. By providing and using several modes, one and the same resonator can be used multiple times.

[56] By way of example, the following implementation forms are presented.

[57] Full-Reflection-Mode-Converter (FRC) (Figure 6): Reflects the entire incident wave, converting it into complementary mode. The relationship between DC and push-pull mode is given in a phase difference of 180 ° for a path. The incoming wave is reflected at the upper path idle by a factor of I = r and reflected at short circuit of the lower path by 1 - = r, thus satisfying the phase requirement for mode conversion.

[58] Partial reflection mode converter (PRC) (Figure 7): The incident wave is partially reflected and converted, partially transmitted without conversion. The desired ratio between reflection and transmission can be selected. In practice, high reflection and low transmittance values make sense, since they are the least stressful for the internal resonator system. Based on the principle of the FRC, only a nearly ideal idling and a nearly ideal short circuit are used here. For idle, this could represent a very small series capacity or a very large series inductance. len. The almost ideal short circuit could be a low shunt inductance or a large shunt capacity. According to the theory of conduction, the wave divides into a reflection part and a transmission part in the case of this impedance jump on the line. The reflection factors are close to 1 = r and 1 = r, respectively, but are slightly different due to the non-ideality of the terminations thereof. By means of this component deviating from one, which represents the transmission factor of the component, the incident wave is transmitted to a corresponding extent in its original mode.

[59] Resonance Reflection Mode Converter (RRC) (Figure 8): This mode converter also builds on the principle of FRC. Deviating from the ideal idling is replaced by a parallel resonant circuit and the ideal short circuit through a series resonant circuit. Thus, ideal conversion conditions are only given exactly at resonant frequency, resulting in a broadband conversion result overall. A disadvantage of the in the illustrated RRC version is that both resonators must have the same resonant frequency and still further resonances can occur. Important special forms of this RRC are the reduced structures with only one resonator and a short circuit or Leer¬ run. If one uses a short circuit for 82, one can consider the remaining mode converter as a single resonator and FRC. Consequently, a dual-mode resonator system can also consist solely of a switching network and an RRC.

[6O] In the following, some examples of dual-mode resonator systems are presented. However, due to the possible DC or push-pull coupling, the possible use of series and parallel resonant circuits as resonators, the possible mode converters and a very large number of implementation forms for a coupling network can not be listed in detail.

[61] An example of resonator systems for reflection use with push-pull supply is shown in Figure 9. In the left half of the figure (a), a "classical" symmetric reflection resonator is coupled via the two coupling capacitors 92. In this case, too, these small capacitors provide for an impedance transformation or weak coupling and ultimately for an improved selectivity The same internal resonator (here 96) is used as in the left-hand part of Figure 9. The coupling capacitors 97 also do not differ in value from those in 92. On the one hand, the mode converter (FRC) consisting of a short circuit 94 and an open circuit 95 is new As mentioned above, this unit can also be considered as RRC in combination with the resonator. manoeuvrable. In this example, the common mode fashion blocker was implemented by the network 98. At the resonance frequency, the two associated coils form a short circuit with the capacitor connected to ground for the common-mode signal. For the push-pull signal, however, only the coils are effective. These form with the capacitors 97, if necessary, an impedance transformation.

[62] A very simple example of resonator systems for reflection use with common mode sensing is illustrated in FIG. In the left half of the figure (a), again, a "classical" non-symmetrical reflection resonator is coupled to the inner resonator element 101 via the coupling capacitor 102. In this case too, this small capacitor ensures impedance transformation or weak coupling and The same inner resonator (here 103) as in the left part is used in the right-hand part of the figure 10. Also, the coupling capacitors 104 do not have to differ in value from the value of 102. On the one hand, the fashion is new As mentioned above, in this case the necessary mode blocker can simply be made up of the interconnection of the two capacitors 104. Thus, in comparison to the previous circuit, only one additional coupling element is required.

[63] A dual-mode resonator system can be constructed in a similar way as before from a known resonator for the transmission insert according to FIG. The reaction is carried out in complete analogy to the previously introduced.

[64] A particularly popular implementation of an adjustable oscillator in integrated circuit technology (semiconductor technology) is that of the differential VCO shown in Figure 11.

[65] The usual synthetic approach for the development of a differential VCO is the principle of "negative input resistance." The resonator given by the inductors 111 and 112 and the variable capacitance 113 is attenuated in this arrangement Characteristic characteristic of the transistors 114 in the working area the lossy resonant circuit connected in parallel with a negative resistance, which compensates for the losses.

[66] Due to the differential arrangement, it is possible that the maximum voltage swing in the resonator exceeds the supply voltage. The higher this maximum level fails, the better the expected noise performance of the oscillator. This property thus directly affects an improvement of the phase noise. Here are the reasons for the popularity of this concept. From the point of view of a high-frequency engineer, impedance transformation, which is not shown in the simplified Figure 11, is the reason for the voltage increase and the better selectivity associated therewith. [67] With a multi-mode approach and the use of the dual-mode resonator system, a further understanding of the system can be applied. Figure 12 shows a block diagram of the dual-mode oscillator.

[68] The push-push amplifier in differential cross-structure can be interpreted as a push-pull reflection amplifier. The transistors are both in an emitter circuit. A signal entering the base on a path is amplified with a phase shift of 180 ° and returned to the other path via the crossed collectors. So there is a reflection of the push-pull with a reflection factor of MJ ₂ = - CC, where α corresponds to the set gain of the transistors.

[69] A sequence of the oscillation condition is divided into the following steps: The amplified push-pull wave is coupled through the coupling network with the integrated common mode blocker without influencing the resonator system and passes through the resonator. After the subsequent reflection and mode conversion into the common mode, the inner resonator element is transmitted a second time. Subsequently, the mode blocker structure with a common-mode reflection factor of M ^ _x = -1 ensures a further passage of the resonator system. The wave traverses the resonator again, is converted back into the push-pull mode at the reflection mode converter, filtered again by the resonator element and only now leaves the dual-mode resonator system and is again amplified as a push-pull signal.

[70] By using the dual-mode resonator system, the phase noise can be reduced by a further 6 dB. This was verified by simulations and measurements. The signal of this VCO can finally be coupled as a push-pull signal to 121 or behind an optional balun as an unbalanced signal at 122.

[71] Only if one realizes the most primitive differential VCO according to Figure 11, this mono-mode solution has fewer components than the dual-mode VCO. Often one already uses for the mono-mode solution an impedance transformation, as shown in Figure 12. As already mentioned, the impedance transformation noticeably reduces the phase noise. In this case, a DC supply for the power supply of the transistor is needed, which looks the same from the topology as the fashion blocker in Figure 12. Finally, the circuits differ only by the necessary for the mode converter short circuit. That is, the Bau¬ element cost is the same. [72] A very simple oscillator can be realized by coupling back a transistor amplifier via a frequency-selective network as shown in the left half of Figure 14. In the high frequency case, both the transistor circuit and the feedback network around 180 ° phase rotation at the resonant frequency. Thus, in addition to the amplitude filter input, a frequency-selective phase condition is additionally provided which both reduce the phase noise. This concept can be used with the dual-mode resonator by simply using the dual-mode resonator circuit shown in the right-hand part b) of FIG. 14 instead of the part a). This circuit has both a steeper phase response and a factor 2 narrower window for the 3dB corner frequencies, both of which result in a significant reduction in phase noise.

[73] A very common concept for the realization of compact and at the same time effective filter circuits with bandpass properties is the coupling of resonant circuits. Already the coupling of two resonators by one Ld.R. high-resistance reactive component (coil or capacitor). There is some extended coupled resonator filter shown in Figure 13. Through the use of the coupling elements 132 at the input and 134 at the output, the steepness of the flanks can be further improved by the passband. The functional principle of this filter circuit is independent of the type of resonators and couplings used. Any desired resonators as well as coupling elements can be used.

[74] Figure 13 exemplifies the simple case of two LC resonators that are capacitively coupled. Furthermore, the input and the output are also capacitively coupled. Such filter scarfs have in principle adaptation to two closely spaced frequency points. The bandwidth is set by the coupling between the resonators. The edge steepness is characterized by the value of the resonator elements and the input and output couplings.

[75] In analogy to the transmission VCO circuit, the resonators can also be replaced by the new dual-mode resonators according to Figure 14 here. A dual mode filter according to the same principle as illustrated in Figure 13 is shown in Figure 15. The system consists of

- four switching networks,

- and two FRCs.

The four coupling networks are each before and after each resonator FRC and represent both the coupling between the resonators as well as the coupling and decoupling. Another function of the coupling networks is the blocking of the push-pull signal. The mode of operation of the dual-mode filter circuit can be explained in terms of signal theory via a multi-mode representation according to block diagram 5: The system consists of two identically structured sections, each with an FRC between an input and output coupling network.

[77] The incoming single-ended signal is routed to the first FRC via the input coupling network. At this point, the common mode signal is transformed into a push-pull signal.

The push-pull signal is reflected at the Koppekietzwerken with Af _1J = - 1 and returns to the FRC. The result is now more a common mode signal that can pass through the output coupling network of the first section to the input coupling network of the second portion of the circuit. In the same way as in the first section, the second FRC is traversed twice by the signal before the supplied common-mode signal is again available as a common-mode signal at the output of the last switching network.

[78] Through this dual-mode operation, the resonators are used twice each. Their filter properties are thereby markedly increased. This improvement in system performance can be used to steer the flanks more steeply, or to reduce the transmission attenuation by about 30% while maintaining the same slope.

[79] Steeper edges increase the bandwidth yield and improve signal selectivity. Lower transmission attenuation of filters in front-end circuits leads to improved signal-to-smoke ratios. As a result, the received signal can be more clearly recognized and processed, which in the case of analog systems can lead to an increase in the range or alternatively to a reduction in the power consumption. In digital systems, this improved filter performance leads to a minimization of the BER.

Claims

claims:

A resonator system comprising a coupling network, at least one mode blocker, at least one resonator and at least one mode converter, which are connected to one another via a multi-conductor system having at least two signal conductors and a ground, the resonator having a resonant frequency and at least two modes in the resonator system the resonant frequency resonant circuit wave are capable of propagation, wherein the Mode¬ blocker between resonator and coupling network or in the Koppemetzwerk is arranged and one of the two modes does not leave the resonator and wherein the Modekon¬ verter a first in the mode converter incoming mode of the two modes in the other fashion of the two modes transferred.

2. Resonator system according to claim 1, characterized by at least one three-conductor system in the interior, consisting of two signal conductors and a ground in which only TEM waves, which are referred to as DC and push-pull mode, are capable of propagation, and with one or more resonator elements whose physical realization form and manufacturing technology are arbitrary, which makes it possible that between two electrical terminals a series or ei¬ ne parallel resonance occurs at the resonant frequency fö, where a. either a resonator element or a plurality of structurally identical resonator elements between the signal conductors and / or are connected by a signal conductor to ground, having either a series or a parallel resonance, or n * 2 (n = l, 2, 3, ...) identical resonator elements having either a series or a parallel resonance, connected in series or crossed to the signal conductors, b. one or two mode converters are connected in series with the resonator element or the resonator elements, or a mode converter is already connected under a. has been realized, which converts a push-pull mode from a common mode and vice versa as a reflected signal and possibly transmits a small part of the signal, and c. a coupling network or the coupling circuit can transmit a mode entirely or in part by the resonator system to one or more symmetrical or unbalanced gates and blocks the other mode.

3. resonator system according to claim 1 or 2, characterized in that it is designed as a reflection resonator and a frequency-selective mode converter with one or more

Resonator elements comprises, wherein a. either the mode converter of one or more parallel parallel resonators, which are connected to a signal line and to ground, and an open circuit of the other signal line, and thus only the incident signal at the resonant frequency is reflected as a converted signal. b. or the mode converter of one or more series resonators connected in series, which are connected to a signal line and to ground, and a short circuit of the other signal line and thus only the incident signal at the resonant frequency is reflected as a converted signal c. or the mode converter comprising one or more parallel resonators connected in parallel and connected to a signal line and to ground, and one or more series resonators connected in series to the other signal line and grounded, and thus only the incident signal at the resonant frequency is reflected as a converted signal.

4. resonator system according to one of claims 1 to 3, characterized in that it has a resonant frequency fθ and is designed as a reflection and / or transmission resonator, wherein a. the mode converter consists of either a small grounded inductance and a small series capacitance, or of a large series inductance and a large grounded capacitance, each inserted in a series line, and b. the mode converter consists of a series resonator and a parallel resonator, the resonant frequency of which deviates from fθ, which at fθ is the reactive elements under a. result.

5. resonator system according to one of claims 1 to 4, characterized in that it is realized as a pure reflection resonator, wherein the mode converter consists of a short circuit at ei¬ nem line end and an open circuit at the other end of the line.

6. resonator system according to one of claims 1 to 5, characterized in that it is designed as a resonance component, which is introduced into a two-wire or two-conductor system, wherein a. the coupling network for use as a reflection resonator of two identical Kopel pelelemente for unilateral input or output from the signal conductor of the two-wire System via the common mode on the three-wire system and the push-pull mode is reflected, or b. the coupling network for use as a transmission resonator consists of two identical coupling elements for two-sided input and output from the signal conductor of the two-wire system via the common mode to the three-wire system and the

Push-pull mode is reflected.

7. resonator system according to claim 6, characterized in that the coupling network ver¬ low-loss coupling elements, in particular at least one small capacitor and / or we¬ least one large inductance comprises.

8. A method for increasing the loaded quality of a resonant circuit, characterized in that a first mode of a resonant in a resonator of Schwing¬ circle propagatable resonant circuit is excited via a coupling network, passed through a resonator of the Reso¬ natorsystems and converted into a further mode of this resonant circuit which mode is then also passed through the resonator without completely leaving the resonator system, and then converted back into the first mode.

9. The method according to claim 8, characterized in that the further mode before its Rück¬ conversion passes through the resonator twice.

10. The method according to claim 8 or 9, characterized in that at least one mode is reflected in the conversion.