CA1159118A - V.h.f. filter and transistor biassing circuit - Google Patents
V.h.f. filter and transistor biassing circuitInfo
- Publication number
- CA1159118A CA1159118A CA000354236A CA354236A CA1159118A CA 1159118 A CA1159118 A CA 1159118A CA 000354236 A CA000354236 A CA 000354236A CA 354236 A CA354236 A CA 354236A CA 1159118 A CA1159118 A CA 1159118A
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- CA
- Canada
- Prior art keywords
- filter
- frequency
- bandstop filter
- equal
- quarter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/203—Strip line filters
- H01P1/2039—Galvanic coupling between Input/Output
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Waveguide Connection Structure (AREA)
Abstract
PHF. 79-538 10 ABSTRACT:
A bandstop filter for very high frequency trans-mission lines having distributed constants, comprising several filtering elements each intended to prevent the transmission of a specific frequency band. The first fil-tering element is a quarter-wave filter, the second element an assembly of two transmission paths of a length such that the signals present at the outputs have opposite phases and cancel other, the third element being a quarter-wave filter, these elements being grouped such that they form an extremely compact filter which is quite insensitive to proximity effects. Use for very high frequency filters having wide cutoff bands.
A bandstop filter for very high frequency trans-mission lines having distributed constants, comprising several filtering elements each intended to prevent the transmission of a specific frequency band. The first fil-tering element is a quarter-wave filter, the second element an assembly of two transmission paths of a length such that the signals present at the outputs have opposite phases and cancel other, the third element being a quarter-wave filter, these elements being grouped such that they form an extremely compact filter which is quite insensitive to proximity effects. Use for very high frequency filters having wide cutoff bands.
Description
13~S~
The present invention relates to a bandstop filter for very high frequency transmission lines having distributed constants and implemented in planar structure, more particularly in accordance with the microstrip technique, as well as to a biassing circuit for a very high frequency transistor comprising this filter.
A conventional manner for ensuring the reception of a very high frequency signal is to include in the receiver a mixer which receives on the one hand this useful very high frequency signal of the frequency fS and on the other hand a signal of the frequency fOL produced by a local oscillator and which produces a signal having an intermediate frequency f~I which is equal to the difference between the frequencies fS and fOL. This mixer must be followed by a filter which prevents the transmission of the frequencies fs and fOL and promotes the transmission of the weakest frequency f~I, that is to say a low-pqss filter or at least a band-stop filter.
Such filters are included in the amplifier stage described in "Proceedings of the 4 h ~uropean Microwave Conference", Montreux, September 1974, pages 97 to 100, (see ~ig. 2), or in the oscillator stage described in "Proceedings of the 5th European Microwave Conference", Hamburg, September 1975, pages 296 etc (see ~ig. 4). Nevertheless, when this filter is used alone, as is the case in the second paper, a very narrow band of this filter is cutoff and it i9 not suitable for the above-intended use. When, on the contrary, several filters are used in conjunction, it is possible that a wider band is cutof~ but this is offset by the fact that other disadvantages are created, notably the fact that the overall filter thus realized becomes bulky and no accurate positioning of the filter with respect to the mixer is possible.
It is an object of the invention to provide a bandstop filter for very high frequencies which does not require such compromises which are inevitably little satisfactory, and which is .. .. .
P~ 79-538 -2- 28.05.1980 extremely compact while having a cutoff band which is sufficiently large and offering a properly defined plane of short-circuit with respect to the mixer to optimize the efficiency of this mixer.
To this end the invention relates to a bandstop filter which is characterized in that it comprises.
a) a first filtering element intended to prevent the transmission of a first frequency band and comprised of a quarter-wave filter having electrical length equal to one quarter of the wavelength ~ 1 associated with the centre frequency of this first band, arranged at the input point of the bandstop filter and defining there a plane of short circuit, b) a second filtering element intended to prevent the transmission of a second frequency band which is adjacent to the first band and which is comprised of an assembly of two parallel transmission paths which separate at the input point of the bandstop filter and come together again at the output point of this bandstop filter such, that the electric length of each of these two paths is equal to an odd number of times one quarter of the wavelength 1 2~ which is associated with the centre frequency of the second frequency band and that the difference between these lengths is equal to an odd number of times half this wavelength. Preferably, this second filtering element is a closed loop having an electric length equal to ~ 2 and transversely connected to the very high frequency transmission line in the input and output points of the bandstop filter which are spaced on this loop at a distance equal to l 2/4' and that the first filtering element is positioned within this loop.
lhe bandstop filter thus realised occupies in a very efficient manner very little space, since the combination of these two filtering elements and a proper choice of their dimensions render it possible to obtain the desired width of the cutoff band at one's option. In addition, connecting these two filtering elements to the same point, at the input point of the filter, defines in a unique and accurate manner the plane of short circuit of the signals whose transmission one wants to prevent, which renders the action of the filter in practice PH~ 79-538 -3- 28.05.1980 independent of the frequency in the cutoff band (20 to 30%). In order to render the band which was cutoff by this filter still wider and to eliminate the second harmonic of the centre frequency of either the one or the other of the two frequency bands which were already eliminated by the first and the second filtering elements, this filter may comprise at least a third filtering element intended to prevent the transmission of a third frequency band centered around the frequency of double the centre frequency of the first frequency band and comprised of a quarter-wave filter of the electrical length ~ 1/8~ which is arranged in parallel with one of the two transmission paths at a distance fro~ the input point of the bandstop filter equal to (n~ 2/2, and is a positive integer which is compatible with the length of the transmission path, or, alternatively, intended to prevent the transmission of a third frequency band centered around the frequency which is double the centre -frequency o~ the second frequency band and being comprised of a quarter-wave fil-ter of an electrical length ~ 2/8 arranged in parallel with one of the two transmission paths at a distance from the input point of the bandstop filter equal to (n~ 2/2, and being a positive integer which is compatible with the length of the transmission path.
Further details and advantages of the invention will be better understood from the following description with reference to the accompanying drawings, which show by way of non-limitative examples some embodiments of the invention and in which:
- Fig. 1 shows a first embodiment, having two filtering elements, of the bandstop filter according to the invention;
- Figs. 2a and 2b show two other embodiments having three filtering elements of the bandstop filter according to the invention; and - Fig. 3 shows how the invention can be used to bias a very high frequency transistor.
~he bandstop filter shown in Fig. 1 has an input point ~ to which an upper portion Le f the transmission line incorporating the filter is connected, and an output point S to which a lower portion ~s f this transmission line is connected. According to the invention, this bandstop filter is comprised of a first PH~ 79-5~ -4- 28.05.1980 filtering element 10 and a second filtering element 20, which are intended to prevent the transmission of a first frequency band and a second frequency band adjacent to the first frequency band, respectively.
The element 10 is comprised of a quarterwave filter having an electrical length equal to a quarter wavelength A
which is associated with the centre frequency of the first frequency band and is arranged at the input point ~ of the bandstop filter. The element 20 is comprised of an assembly of two parallel transmission paths 21 and 22, which separate at the input point ~, in the plane of short-circuit defined by the presence of the first filtering element 10, by-pass the element 10 and come together again at the output point S. In the example described here the first transmission path 21 follows a path in the form of an arc of a circle of an electrical length ~ 2/4 ( ~2 being the wavelength associated with the centre frequency of the second frequency band), whereas the second path 22 follows a path in the form of a complementary arc of a circle of an electrical length ~ A 2/4 At point S, where the transmission paths 21 and 22 come together a~ain, the signals having the frequency corresponding to the wavelength ~ 2 arrive therefore in that point S with opposite phases and not any signal of this frequency is transmitted to the portion ~s f the transmission line.
As will be apparent, the bandstop filter has a very small circumference, since the circular shape adopted for the element 20 requires very little space and the first filtering element is placed inside the second element. ~urthermore, the insulation provided by the bandstop filter embodying the invention is excellent, and is only limited by the parasitic coupling (higher modes) which may appear between ~ and S (an attenuation of 60 d~
can, for example, be obtained if one does not want to have a passband higher than some percents).
It will be evident that the electrical length of the two transmission paths may be longer than the electrical length of the above-described example; the only important fact is that each of the two lengths must be equal to an odd number of times the quarter wavelength ~ 2 and that the difference between its lengths must PHF 79-538 -5- 28.05.1980 be equal to ~22 (2m-1) to ensure that the phase opposi~ion has keen properly obtained is S (m may be any positive integer). The above described example, which corresponds to m=1, corresponds to the most compact emkcdiment, which is therefore, and that in more than one respect, the most advantageous emkodiment, on the one hand for appli-cations where a small size of the component is of prime importance, and on the other hand to provide a better concentration of the electric and magnetic fields and thereby rer.der the filter less sensitive to proximity effects.
In the application referred to in the foregoing, the wavelength ~ 1 is, for example, the wavelength which is associated with the received, useful very high frequency signal of the frequency fS which is intended for the mixer (for example a very high frequency diode), and the wavelength ~ 2 is the wavelength which is associated with the signal of the frequency fOL produced by the local oscillator and which is also applied to the mixer. m e lower portion Ls of the transmission line receives only the signal of the frequency fFI, which is porduced by the non-linear component which forms the nixer; the signals of the frequencies fS and fOL cannot reach this portion Ls, because of the combined action of the filtering elements 10 and 20.
An increase of the frequency band which is cut off by the filter embcdying the invention, may ke obtained when, in accordance with Fig. 2a, this filter comprises a third filtering element 30, which has for its purpose to prevent the transmission of a third fre-quency band which is centered around the frequency of double thecentre frequency of the second frequency band. Actually, still refer-ring to the use mentioned in the foregoing, the signal of frequency fOL produced by the local oscillator has an amplitude which gererally is well akove the amplitude of the received, very high frequency signal of the frequency fs~ and the presence of the second harm~nic of this signal of the frequency fOL corre.sponds therefore to a considerable loss in energy. Introducing the third filtering element 30 renders it possible to prevent the transmission of this harmonic and to avoid deterioration of the efficiency resulting from such a tansmission.
This third filtering element may, of course, also be provided, if necessary, to prevent the transmission of a third frequency band centered around the second harmonic of the centre frequency of the PHF 79-538 -6- 28.05.1980 first freque~cy bard, and no longer of the second kand.
In both cases the third filtering element 30 is a quarter-wave filter which is arranged in parallel with the second transmission path 22 at a distance from the input point E of the stopband filter equal to ~ 2/2 (or, when the transmission paths are longer than the transmission paths of the emkodiments shown in the Figures, equal to n ~ 2/2, n being a positive integer which is c~mr patible with the se/lengths). The length of this filter is ~ 2/8 when it is desired to eliminate the second harmonics of the signal o filtered by the second filtering element 20, or ~ 1/8 if it is desired to eliminate the second harmonic of the signal filtered by the first filtering element 10.
Co~pared with Fig. 2a, where the third filtering element 30 is connected to the transmission path 22 on the outer portion of 1~ the ring, Fig. 2b shows a variation of the embcdiment in which this element 30 is directed towards the interior of the ring. This variation is very advantageous as the bandstop filter em~odying the invention remains extremely compact, in spite of the presence of an additional filte~ing element.
In the foregoing description frequent mention has been made of the pricipal use of the filter according to the invention namely its use in a very hiah frequency receiver. Fig. 3 shows an alternative application of the invention, namely incorporation of the bandstop filter in the biassing circuit of a very high frequency txan-sistor. The bandstop filtex according to the invention is connected (perpendicularly in the present case), in its input point E, to a section 40 of the ~xarsmission line which is arranged in parallel with a transmission line 41, which comprises a very high frequency transis-tor 42 and a capacitor 45. The length of the section 40 is equal to ~he quarter wa~telength a~ssociated with the very high f~equency signal which txaverses the txansmission line 41. Furthermore, the filter is connected (perpendicularly) in its output point S, to a p3wer supply circuit 43 of the transistor 42. m is arrangement renders it possible for circuit 43 to ensure biassing of the transistor 42 by txansmitting its biassing voltage through the line section 44, the bandstop filter (for example the filter as shown in Fig. 1) line section 40 and lire 41. Conversely, the very high frequency signal flowing through line 41 cannot reach circuit 43 because of the efficient barrie~ formed by F~IF 79-538 -7- 28.05.1980 the handstop filter. The filtering action is of a higher sti].l efficiency when section 40 is given the highest possible impedance.
It will be apparent that the present invention is not limited to the few embodiments described in the foregoing and shown 5 in the drawings, but that on the b~sis of these enbodiments further embodiments can be realized withaut going beyond the scope of the invention. More particularly, the circular arrangement of the tw~
transmisson paths of the second filtering element is admittedly the most compact arrangement possible, but a square or rectangular arrange-lo ment, for example, remains very cc~pact and is therefor almost as advantageaus as the arrangement described in the foregoing and shcwn in the drawings.
The present invention relates to a bandstop filter for very high frequency transmission lines having distributed constants and implemented in planar structure, more particularly in accordance with the microstrip technique, as well as to a biassing circuit for a very high frequency transistor comprising this filter.
A conventional manner for ensuring the reception of a very high frequency signal is to include in the receiver a mixer which receives on the one hand this useful very high frequency signal of the frequency fS and on the other hand a signal of the frequency fOL produced by a local oscillator and which produces a signal having an intermediate frequency f~I which is equal to the difference between the frequencies fS and fOL. This mixer must be followed by a filter which prevents the transmission of the frequencies fs and fOL and promotes the transmission of the weakest frequency f~I, that is to say a low-pqss filter or at least a band-stop filter.
Such filters are included in the amplifier stage described in "Proceedings of the 4 h ~uropean Microwave Conference", Montreux, September 1974, pages 97 to 100, (see ~ig. 2), or in the oscillator stage described in "Proceedings of the 5th European Microwave Conference", Hamburg, September 1975, pages 296 etc (see ~ig. 4). Nevertheless, when this filter is used alone, as is the case in the second paper, a very narrow band of this filter is cutoff and it i9 not suitable for the above-intended use. When, on the contrary, several filters are used in conjunction, it is possible that a wider band is cutof~ but this is offset by the fact that other disadvantages are created, notably the fact that the overall filter thus realized becomes bulky and no accurate positioning of the filter with respect to the mixer is possible.
It is an object of the invention to provide a bandstop filter for very high frequencies which does not require such compromises which are inevitably little satisfactory, and which is .. .. .
P~ 79-538 -2- 28.05.1980 extremely compact while having a cutoff band which is sufficiently large and offering a properly defined plane of short-circuit with respect to the mixer to optimize the efficiency of this mixer.
To this end the invention relates to a bandstop filter which is characterized in that it comprises.
a) a first filtering element intended to prevent the transmission of a first frequency band and comprised of a quarter-wave filter having electrical length equal to one quarter of the wavelength ~ 1 associated with the centre frequency of this first band, arranged at the input point of the bandstop filter and defining there a plane of short circuit, b) a second filtering element intended to prevent the transmission of a second frequency band which is adjacent to the first band and which is comprised of an assembly of two parallel transmission paths which separate at the input point of the bandstop filter and come together again at the output point of this bandstop filter such, that the electric length of each of these two paths is equal to an odd number of times one quarter of the wavelength 1 2~ which is associated with the centre frequency of the second frequency band and that the difference between these lengths is equal to an odd number of times half this wavelength. Preferably, this second filtering element is a closed loop having an electric length equal to ~ 2 and transversely connected to the very high frequency transmission line in the input and output points of the bandstop filter which are spaced on this loop at a distance equal to l 2/4' and that the first filtering element is positioned within this loop.
lhe bandstop filter thus realised occupies in a very efficient manner very little space, since the combination of these two filtering elements and a proper choice of their dimensions render it possible to obtain the desired width of the cutoff band at one's option. In addition, connecting these two filtering elements to the same point, at the input point of the filter, defines in a unique and accurate manner the plane of short circuit of the signals whose transmission one wants to prevent, which renders the action of the filter in practice PH~ 79-538 -3- 28.05.1980 independent of the frequency in the cutoff band (20 to 30%). In order to render the band which was cutoff by this filter still wider and to eliminate the second harmonic of the centre frequency of either the one or the other of the two frequency bands which were already eliminated by the first and the second filtering elements, this filter may comprise at least a third filtering element intended to prevent the transmission of a third frequency band centered around the frequency of double the centre frequency of the first frequency band and comprised of a quarter-wave filter of the electrical length ~ 1/8~ which is arranged in parallel with one of the two transmission paths at a distance fro~ the input point of the bandstop filter equal to (n~ 2/2, and is a positive integer which is compatible with the length of the transmission path, or, alternatively, intended to prevent the transmission of a third frequency band centered around the frequency which is double the centre -frequency o~ the second frequency band and being comprised of a quarter-wave fil-ter of an electrical length ~ 2/8 arranged in parallel with one of the two transmission paths at a distance from the input point of the bandstop filter equal to (n~ 2/2, and being a positive integer which is compatible with the length of the transmission path.
Further details and advantages of the invention will be better understood from the following description with reference to the accompanying drawings, which show by way of non-limitative examples some embodiments of the invention and in which:
- Fig. 1 shows a first embodiment, having two filtering elements, of the bandstop filter according to the invention;
- Figs. 2a and 2b show two other embodiments having three filtering elements of the bandstop filter according to the invention; and - Fig. 3 shows how the invention can be used to bias a very high frequency transistor.
~he bandstop filter shown in Fig. 1 has an input point ~ to which an upper portion Le f the transmission line incorporating the filter is connected, and an output point S to which a lower portion ~s f this transmission line is connected. According to the invention, this bandstop filter is comprised of a first PH~ 79-5~ -4- 28.05.1980 filtering element 10 and a second filtering element 20, which are intended to prevent the transmission of a first frequency band and a second frequency band adjacent to the first frequency band, respectively.
The element 10 is comprised of a quarterwave filter having an electrical length equal to a quarter wavelength A
which is associated with the centre frequency of the first frequency band and is arranged at the input point ~ of the bandstop filter. The element 20 is comprised of an assembly of two parallel transmission paths 21 and 22, which separate at the input point ~, in the plane of short-circuit defined by the presence of the first filtering element 10, by-pass the element 10 and come together again at the output point S. In the example described here the first transmission path 21 follows a path in the form of an arc of a circle of an electrical length ~ 2/4 ( ~2 being the wavelength associated with the centre frequency of the second frequency band), whereas the second path 22 follows a path in the form of a complementary arc of a circle of an electrical length ~ A 2/4 At point S, where the transmission paths 21 and 22 come together a~ain, the signals having the frequency corresponding to the wavelength ~ 2 arrive therefore in that point S with opposite phases and not any signal of this frequency is transmitted to the portion ~s f the transmission line.
As will be apparent, the bandstop filter has a very small circumference, since the circular shape adopted for the element 20 requires very little space and the first filtering element is placed inside the second element. ~urthermore, the insulation provided by the bandstop filter embodying the invention is excellent, and is only limited by the parasitic coupling (higher modes) which may appear between ~ and S (an attenuation of 60 d~
can, for example, be obtained if one does not want to have a passband higher than some percents).
It will be evident that the electrical length of the two transmission paths may be longer than the electrical length of the above-described example; the only important fact is that each of the two lengths must be equal to an odd number of times the quarter wavelength ~ 2 and that the difference between its lengths must PHF 79-538 -5- 28.05.1980 be equal to ~22 (2m-1) to ensure that the phase opposi~ion has keen properly obtained is S (m may be any positive integer). The above described example, which corresponds to m=1, corresponds to the most compact emkcdiment, which is therefore, and that in more than one respect, the most advantageous emkodiment, on the one hand for appli-cations where a small size of the component is of prime importance, and on the other hand to provide a better concentration of the electric and magnetic fields and thereby rer.der the filter less sensitive to proximity effects.
In the application referred to in the foregoing, the wavelength ~ 1 is, for example, the wavelength which is associated with the received, useful very high frequency signal of the frequency fS which is intended for the mixer (for example a very high frequency diode), and the wavelength ~ 2 is the wavelength which is associated with the signal of the frequency fOL produced by the local oscillator and which is also applied to the mixer. m e lower portion Ls of the transmission line receives only the signal of the frequency fFI, which is porduced by the non-linear component which forms the nixer; the signals of the frequencies fS and fOL cannot reach this portion Ls, because of the combined action of the filtering elements 10 and 20.
An increase of the frequency band which is cut off by the filter embcdying the invention, may ke obtained when, in accordance with Fig. 2a, this filter comprises a third filtering element 30, which has for its purpose to prevent the transmission of a third fre-quency band which is centered around the frequency of double thecentre frequency of the second frequency band. Actually, still refer-ring to the use mentioned in the foregoing, the signal of frequency fOL produced by the local oscillator has an amplitude which gererally is well akove the amplitude of the received, very high frequency signal of the frequency fs~ and the presence of the second harm~nic of this signal of the frequency fOL corre.sponds therefore to a considerable loss in energy. Introducing the third filtering element 30 renders it possible to prevent the transmission of this harmonic and to avoid deterioration of the efficiency resulting from such a tansmission.
This third filtering element may, of course, also be provided, if necessary, to prevent the transmission of a third frequency band centered around the second harmonic of the centre frequency of the PHF 79-538 -6- 28.05.1980 first freque~cy bard, and no longer of the second kand.
In both cases the third filtering element 30 is a quarter-wave filter which is arranged in parallel with the second transmission path 22 at a distance from the input point E of the stopband filter equal to ~ 2/2 (or, when the transmission paths are longer than the transmission paths of the emkodiments shown in the Figures, equal to n ~ 2/2, n being a positive integer which is c~mr patible with the se/lengths). The length of this filter is ~ 2/8 when it is desired to eliminate the second harmonics of the signal o filtered by the second filtering element 20, or ~ 1/8 if it is desired to eliminate the second harmonic of the signal filtered by the first filtering element 10.
Co~pared with Fig. 2a, where the third filtering element 30 is connected to the transmission path 22 on the outer portion of 1~ the ring, Fig. 2b shows a variation of the embcdiment in which this element 30 is directed towards the interior of the ring. This variation is very advantageous as the bandstop filter em~odying the invention remains extremely compact, in spite of the presence of an additional filte~ing element.
In the foregoing description frequent mention has been made of the pricipal use of the filter according to the invention namely its use in a very hiah frequency receiver. Fig. 3 shows an alternative application of the invention, namely incorporation of the bandstop filter in the biassing circuit of a very high frequency txan-sistor. The bandstop filtex according to the invention is connected (perpendicularly in the present case), in its input point E, to a section 40 of the ~xarsmission line which is arranged in parallel with a transmission line 41, which comprises a very high frequency transis-tor 42 and a capacitor 45. The length of the section 40 is equal to ~he quarter wa~telength a~ssociated with the very high f~equency signal which txaverses the txansmission line 41. Furthermore, the filter is connected (perpendicularly) in its output point S, to a p3wer supply circuit 43 of the transistor 42. m is arrangement renders it possible for circuit 43 to ensure biassing of the transistor 42 by txansmitting its biassing voltage through the line section 44, the bandstop filter (for example the filter as shown in Fig. 1) line section 40 and lire 41. Conversely, the very high frequency signal flowing through line 41 cannot reach circuit 43 because of the efficient barrie~ formed by F~IF 79-538 -7- 28.05.1980 the handstop filter. The filtering action is of a higher sti].l efficiency when section 40 is given the highest possible impedance.
It will be apparent that the present invention is not limited to the few embodiments described in the foregoing and shown 5 in the drawings, but that on the b~sis of these enbodiments further embodiments can be realized withaut going beyond the scope of the invention. More particularly, the circular arrangement of the tw~
transmisson paths of the second filtering element is admittedly the most compact arrangement possible, but a square or rectangular arrange-lo ment, for example, remains very cc~pact and is therefor almost as advantageaus as the arrangement described in the foregoing and shcwn in the drawings.
Claims (5)
1. A bandstop filter for very high frequency trans-mission lines having distributed constants and implemented in a planar structure, more particularly in accordance with the microstrip technique, characterized in that it comprises:
a) a first filtering element intended to prevent the trans-mission of a first frequency band and comprised of a quarter-wave filter having an electrical length equal to one quarter of the wavelength .lambda.1 associated with the centre frequency of this first band, arranged at the input point of the bandstop filter and defining there a plane of short circuit, b) a second filtering element intended to prevent the trans-mission of a second frequency band which is adjacent to the first band and comprised of an assembly to two parallel transmission paths which separate at the input point of the bandstop filter and come together again at the output point of this bandstop filter such, that the electrical length of each of these two paths is equal to an odd number of times one quarter of the wavelength .lambda. 2 associated with the centre frequency of the second frequency band and that the difference between these lengths is equal to an odd number of times half this wavelength.
a) a first filtering element intended to prevent the trans-mission of a first frequency band and comprised of a quarter-wave filter having an electrical length equal to one quarter of the wavelength .lambda.1 associated with the centre frequency of this first band, arranged at the input point of the bandstop filter and defining there a plane of short circuit, b) a second filtering element intended to prevent the trans-mission of a second frequency band which is adjacent to the first band and comprised of an assembly to two parallel transmission paths which separate at the input point of the bandstop filter and come together again at the output point of this bandstop filter such, that the electrical length of each of these two paths is equal to an odd number of times one quarter of the wavelength .lambda. 2 associated with the centre frequency of the second frequency band and that the difference between these lengths is equal to an odd number of times half this wavelength.
2. A bandstop filter as claimed in Claim 1, char-acterized in that the second filtering element is a closed loop of an electrical length equal to .lambda. 2 and being trans-versely connected to the very high frequency transmission line in the input and output points of the bandstop filter at a mutual distance equal to A 2/4 and in that the first filtering element is arranged within this loop.
3. A bandstop filter as claimed in Claim 1 or Claim 2, characterized in that it comprises at least a third filtering element intended to prevent the transmis-PHF. 79-538 9 sion of a third frequency band which is centred around the frequency of double the centre frequency of the first frequency band and comprised of a quarter wave filter having an electrical length A 1/8 arranged in parallel with one of the two transmission paths at a distance from the input point of the bandstop filter equal to (n-l) .lambda. 2/2, n being a positive integer which is compatible with the length of the transmission path.
4. A bandstop filter as claimed in Claim 1 or 2, characterized in that it comprises at least a third fil-tering element intended to prevent the transmission of a third frequency band which is centered around the frequency which is double the centre frequency of the second frequency band and comprised of a quarter wave filter having an elec-trical length .lambda.2/8 arranged in parallel with one of the two transmission paths at a distance from the input point of the bandstop filter equal to (n-I) .lambda. 2/2, n being a positive integer which is compatible with the length of the transmis-sion path.
5. A biassing circuit for a very high frequency transistor, comprising a bandstop filter as claimed in Claim 1 and characterized in that the input point of the filter is transversely connected to a section of the transmission line which itself is arranged in parallel with a further trans-mission line which is connected to the very high frequency transistor, and in that the output point of the filter is connected perpendicularly to a power supply circuit of this transistor, the electrical length of the section between the input point of the bandstop filter and the said further transmission line being equal to one quarter of the wave-length associated with the very high operating frequency.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7916260A FR2460049A1 (en) | 1979-06-25 | 1979-06-25 | BANDWHEEL FILTER FOR A HYPERFREQUENCY TRANSMISSION LINE AND A MICROWAVE TRANSISTOR POLARIZATION CIRCUIT COMPRISING THE FILTER |
| FR7916260 | 1979-06-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159118A true CA1159118A (en) | 1983-12-20 |
Family
ID=9227049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000354236A Expired CA1159118A (en) | 1979-06-25 | 1980-06-18 | V.h.f. filter and transistor biassing circuit |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0021523B1 (en) |
| JP (1) | JPS566501A (en) |
| AU (1) | AU536334B2 (en) |
| BR (1) | BR8003890A (en) |
| CA (1) | CA1159118A (en) |
| DE (1) | DE3071590D1 (en) |
| FR (1) | FR2460049A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2510326A1 (en) * | 1981-07-24 | 1983-01-28 | Thomson Csf | LINEAR RESONATOR PASSER FILTER OPEN TO THEIR TWO ENDS |
| FR2517491A1 (en) * | 1981-11-27 | 1983-06-03 | Labo Electronique Physique | COMBINER-MIXER WITH DOUBLE SOURCE TRANSISTOR |
| DE69332249T2 (en) * | 1992-04-30 | 2003-04-10 | Matsushita Electric Industrial Co., Ltd. | Loop-shaped, dual-mode strip resonator for allowing microwaves to resonate in two modes and bandpass filters with the resonators |
| JP5749133B2 (en) * | 2011-10-04 | 2015-07-15 | 古河電気工業株式会社 | High frequency module |
| JP7133486B2 (en) * | 2019-01-16 | 2022-09-08 | 日立Astemo株式会社 | signal transmission device, signal transmission system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR72524E (en) * | 1951-05-23 | 1960-04-14 | Int Standard Electric Corp | Transmission system for high frequency |
| BE519797A (en) * | 1952-05-08 | |||
| US3150325A (en) * | 1962-04-12 | 1964-09-22 | Donald J Blattner | Wide band traveling wave parametric amplifier |
| DE2453605B2 (en) * | 1974-11-12 | 1976-09-09 | Siemens AG, 1000 Berlin und 8000 München | WAVE GUIDE COUPLER FOR EQUAL DISTRIBUTION OR INTERCONNECTION OF SIGNAL ENERGY |
| JPS5352336A (en) * | 1976-10-22 | 1978-05-12 | Mitsubishi Electric Corp | Dividing filter |
| DE2804118C2 (en) * | 1978-01-31 | 1982-03-04 | Siemens AG, 1000 Berlin und 8000 München | Microwave ring hybrid circuit in stripline technology |
| US4185252A (en) * | 1978-05-10 | 1980-01-22 | The United States Of America As Represented By The Secretary Of The Army | Microstrip open ring resonator oscillators |
| FR2451110A1 (en) * | 1979-03-06 | 1980-10-03 | Labo Electronique Physique | MICROWAVE IMAGE FREQUENCY REFLECTION FILTER |
-
1979
- 1979-06-25 FR FR7916260A patent/FR2460049A1/en active Granted
-
1980
- 1980-06-17 EP EP19800200567 patent/EP0021523B1/en not_active Expired
- 1980-06-17 DE DE8080200567T patent/DE3071590D1/en not_active Expired
- 1980-06-18 CA CA000354236A patent/CA1159118A/en not_active Expired
- 1980-06-23 AU AU59514/80A patent/AU536334B2/en not_active Ceased
- 1980-06-23 JP JP8504780A patent/JPS566501A/en active Granted
- 1980-06-23 BR BR8003890A patent/BR8003890A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE3071590D1 (en) | 1986-06-12 |
| JPS6322481B2 (en) | 1988-05-12 |
| JPS566501A (en) | 1981-01-23 |
| AU536334B2 (en) | 1984-05-03 |
| FR2460049B1 (en) | 1983-07-08 |
| AU5951480A (en) | 1981-01-08 |
| BR8003890A (en) | 1981-01-13 |
| EP0021523A1 (en) | 1981-01-07 |
| FR2460049A1 (en) | 1981-01-16 |
| EP0021523B1 (en) | 1986-05-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |