JP2008277938A - Strip line resonator and micro strip line resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strip line resonator and a micro strip line resonator which make phase noise characteristics of a voltage controlled oscillator good. <P>SOLUTION: The voltage controlled oscillator 20 includes a resonator 10, a micro strip line conductor 18 for phase adjustment, an active element 22 including a FET of an oscillation element, and an oscillation output terminal 24. The resonator 10 includes a variable voltage source 11 which generates DC voltage, a first micro strip line conductor 14 of a circle or fan shape, a second micro strip line conductor 16 of a circle or fan shape, and a variable capacitance diode 12. Moreover, the first and the second micro strip line conductors which are of different electric lengths and are connected in parallel, compose an LC parallel resonating circuit, and make a composite strip line conductor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stripline resonator and a microstripline resonator used in voltage controlled oscillators for microwave bands and millimeter wave bands.

  2. Description of the Related Art Conventionally, a voltage-controlled oscillator used in a microwave band and a millimeter wave band radio communication device has used a microstrip line resonator or the like in order to improve phase noise characteristics.

  FIG. 9 shows a conventional voltage controlled oscillator 200 shown in Patent Document 1. A voltage-controlled oscillator 200 shown in the figure includes a resonator 100, a phase adjusting microstrip line conductor 108, an active element 112 including an oscillation element FET, and an oscillation output terminal 114.

  Furthermore, the resonator 100 includes a variable voltage power source 101 that generates a DC voltage, a first resonance circuit including a tip-open microstrip line conductor 106, a variable capacitance diode 102, and a first microstrip line conductor 104. And a second resonance circuit configured.

  In such a voltage controlled oscillator 200, microstrip line conductors having different electrical lengths are connected in parallel to provide the first and second resonance circuits, and the setting conditions of each resonance circuit are made different so that a desired frequency at the oscillation frequency fo can be obtained. Gaining characteristics. The oscillation frequency fo is set according to the magnitude of the DC voltage applied from the variable voltage power source 101 to the variable capacitance diode 102.

  In the voltage controlled oscillator 200, in order to set the Q value of the resonator 100 near the resonance frequency to a high value, the frequency at which the reflection phase of the second resonance circuit is 180 deg. It is set higher than the oscillation frequency fo of the oscillator 200. Furthermore, the frequency at which the reflection phase of the first resonance circuit becomes 180 deg is set lower than the oscillation frequency fo so that the resonance frequency of the resonator 100 matches the oscillation frequency fo.

  It is known that the phase noise characteristic in the voltage controlled oscillator 200 is better as the Q value of the resonator 100 is higher. The Q value of the resonator 100 can be expressed by the overall phase inclination of the resonator 100, and this phase inclination is obtained by superimposing the phase inclinations at the resonance frequencies of two resonance circuits connected in parallel.

  However, in the resonator 100 shown in FIG. 9, the Q value is deteriorated by the variable capacitance diode 102 connected to the tip of the resonator 100, so that there is a limit to the reduction in phase noise.

  On the other hand, Patent Document 2 discloses a technique that can devise a stripline conductor and improve the phase noise characteristics by using a fan-shaped stripline conductor.

JP 2003-309431 A JP 2001-284919 A

  Even if the fan-shaped stripline conductor described in Patent Document 2 is used in the voltage controlled oscillator disclosed in Patent Document 1, the open-ended microstripline conductor 106 shown in FIG. Although the Q value can be improved by replacing the strip conductor, the configuration in which the Q value is deteriorated by the resonator 100 and the variable capacitance diode 102 is not changed.

  Therefore, an object of the present invention is to provide a voltage controlled oscillator that can improve the phase noise characteristics and further increase the Q value.

  In order to achieve the above object, a stripline resonator according to the present invention is connected to two dielectrics, a stripline conductor sandwiched between the two dielectrics, and a feeding point of the stripline conductor. In the stripline resonator in which ground conductors are formed on both surfaces of the dielectric substrate including the feed terminal, the stripline conductor is formed by connecting two open end strip strip conductors having different electrical lengths in parallel, and the open end strip The line conductor is characterized by being circular or fan-shaped having a radius from a feeding point and a predetermined angle.

  Moreover, the microstrip line resonator according to the present invention is a microstrip line resonator having a ground conductor formed on one surface of a dielectric and a microstrip line conductor provided on the opposite surface of the ground conductor. In the microstrip line conductor, two open end microstrip line conductors having different electrical lengths are connected in parallel, and the open end microstrip line conductor has a circular shape or a sector shape having a radius from a feeding point and a predetermined angle. It is characterized by that.

  Further, in the stripline resonator according to the present invention, the two tip open stripline conductors are two circles or sectors sharing one feeding point, and combinations thereof, and the two tip open stripline conductors are arranged in parallel. By connecting, the LC parallel resonance circuit is inductive at an electrical length longer than λ / 4 and becomes capacitive at an electrical length shorter than λ / 4.

  Furthermore, in the microstrip line resonator according to the present invention, the two tip open microstrip line conductors are two circles or sectors sharing one feeding point, and a combination thereof, and two tip open microstrips. By connecting line conductors in parallel, the LC parallel resonance circuit is inductive at an electrical length longer than λ / 4 and capacitive at an electrical length shorter than λ / 4.

  Furthermore, in the stripline resonator according to the present invention, the grounding conductor has a through hole for passing a via, and another dielectric layer is laminated on the grounding conductor to feed the open-ended stripline conductor. From the point, the tip open strip line conductor is fed through a through hole of one ground conductor and a via hole extending to the surface of another dielectric layer.

  Furthermore, in the microstripline resonator according to the present invention, a through-hole for passing a via is formed in one ground conductor, and another dielectric layer is laminated on the ground conductor, and the tip open microstripline conductor The open-ended microstrip line conductor is fed from the feed point through a via hole of one ground conductor and a via hole extending to the surface of another dielectric layer.

  Furthermore, the stripline resonator according to the present invention is characterized in that two tip open stripline conductors are separately arranged in different dielectric layers.

  Furthermore, in the microstripline resonator according to the present invention, two tip open microstripline conductors are separately arranged in different dielectric layers.

  When the present invention is used, an LC parallel resonant circuit is configured by connecting stripline conductors or microstripline conductors having different electrical lengths in parallel, and the stripline conductor is formed into a composite stripline conductor in a circular shape or a sector shape. There is an effect that the inclination can be increased, the phase noise characteristic is improved, and a higher Q value can be obtained as compared with the prior art.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 shows the configuration of a voltage controlled oscillator 20 having inductive and capacitive microstrip line conductors according to an embodiment. Here, the difference from the prior art shown in FIG. 9 is that the first and second microstrip line conductors (14, 16), which are two open end microstrip line conductors, are used.

  A voltage controlled oscillator 20 shown in FIG. 1 includes a resonator 10, a phase adjusting microstrip line conductor 18, an active element 22 including an oscillation element FET, and an oscillation output terminal 24. The resonator 10 of the voltage controlled oscillator 20 includes a variable voltage power source 11 that generates a DC voltage, a circular or fan-shaped first microstrip line conductor 14, a circular or fan-shaped second microstrip line conductor 16, and a variable capacitance diode. 12. The feeding points for the first and second microstrip line conductors 14 and 16 are separate.

  FIG. 2 shows a configuration of another voltage controlled oscillator 30 according to the present embodiment. What is characteristic in this embodiment is that the first and second microstrip line conductors are combined to form a composite microstrip line conductor 17 sharing a feeding point. The other configuration is the same as that shown in FIG.

  FIG. 3 shows the layer configuration of the resonator according to this embodiment. The resonator shown in FIG. 3 (a) has two dielectrics, a composite microstrip line conductor 17 provided between the two dielectrics 13, and a ground conductor 15 outside the dielectric. Yes.

  The resonator shown in FIG. 3B includes a dielectric 13 having a ground conductor on one side, a composite microstrip line conductor 17 provided on the opposite side of the dielectric 13, and a composite microstrip line conductor 17. And a shield member 19 for applying an electromagnetic shield.

  Further, the resonator shown in FIG. 3C has the resonator shown in FIG. 3B arranged upside down, further provided with a dielectric 13 on the ground conductor, and feeds power from the upper surface through the VIA hole.

  FIG. 4 illustrates the relationship between the two stripline conductors and each layer according to this embodiment. In FIG. 4 (d), inductive and capacitive microstrip line conductors (14, 16) are used instead of the composite strip line conductor of the resonator shown in FIG. 21 is provided. In the present embodiment, for example, by disposing the fan-shaped microstrip line conductor in one direction on the left side of FIG. 4D, the mounting density can be increased.

  In FIG. 4E, a power supply terminal 21 is provided via a VIA hole from a power supply point located at the center of the composite microstrip line conductor 17 shown in FIG.

  FIG. 5 is a view as seen from the power supply terminal 21 side of FIG. 4E, and illustrates the form of the composite microstrip line conductor 17 sandwiched between the dielectrics 13. FIG. 5 (f) shows from the left a region that has an inner angle of radii r1 and 90 deg and can be regarded as a second microstripline conductor, and an inner angle of radii r2 and 90deg that is regarded as a first microstripline conductor. And an area that can be used.

  FIG. 5 (g) shows, from the lower left, a region that has an inner angle of radii r1 and 270 deg and can be regarded as a second microstrip line conductor, and a first microstrip line conductor that has an inner angle of radii r2 and 90 deg. And an area that can be considered.

  Further, FIG. 5 (h) shows, from the upper left, a region having an inner angle of radii r1 and 90 deg and can be regarded as a second microstrip line conductor, and an inner angle of radii r2 and 270 deg and a first microstrip line conductor And an area that can be considered. As described above, various microstrip line conductors can be designed by changing the radius and the inner angle of the two microstrip line conductors as exemplified by a plurality of forms.

  FIG. 6 shows the composite microstrip line conductor (FIG. 6 (i)) calculated by the inventor through simulation and the fan microstrip line conductor (FIG. 6 (j)) according to the prior art in the same ratio. ing. In this examination, for example, the oscillation frequency fo is set to 4.5 GHz.

  FIG. 7 shows the phase characteristics with respect to the frequency of the voltage controlled oscillator in the present embodiment. In the figure, the characteristic of the first microstrip line conductor (shown as the first line characteristic), the characteristic of the second microstrip line conductor (shown as the second line characteristic), and characteristic matters are circled. As shown.

  FIG. 8 shows the phase characteristics with respect to the frequency of the voltage controlled oscillator according to the prior art. Further, in the figure, characteristic items of the conventional characteristics are shown. Hereinafter, a description will be given with reference to FIGS.

  The first microstrip line conductor 14 in FIG. 6 (i) has a series resonance point at a frequency (for example, 3.1 GHz) having an electrical length λ / 4, and the reflection phase at that time is shown in the upper left of FIG. Thus, 180 deg is obtained. The frequency at which the reflection phase of the first microstrip line conductor 14 becomes 180 deg was set to a value lower than the oscillation frequency fo so that the resonance frequency of the resonator 100 matches the oscillation frequency fo.

  Further, in order to set a high Q value of the resonator near the resonance frequency, the second microstrip line conductor 16 in FIG. 6 (i) has a frequency (for example, 5.9 GHz) having an electrical length λ / 4. The frequency at which the reflection phase is 180 deg at that time is set higher than the oscillation frequency fo of the voltage controlled oscillator as shown in the upper right of FIG.

  As shown in FIG. 7, at the parallel resonance point, the first microstrip line conductor 14 exhibits inductivity (L property). Similarly, at the parallel resonance point, the second microstrip line conductor 16 exhibits capacitance (C property). Indicates. Therefore, when stripline conductors having different electrical lengths are connected in parallel, it can be regarded as an LC parallel resonant circuit at a frequency between both series resonant frequencies. In addition, since the phase changes 360 deg between the two series resonance frequencies, the phase changes abruptly when the difference between the series resonance frequencies is small, so that the phase gradient increases and the Q becomes high.

  As described above, the Q value of the resonator exhibiting the phase noise characteristic can be expressed by the overall phase tilt of the resonator, and this phase tilt is represented by the parallel resonant frequency in the circle in the center of FIG. The phase gradients at the two resonance frequencies connected in parallel are superimposed.

  On the other hand, the fan-shaped microstrip line conductor shown in FIG. 6 (j) has a resonance point at a frequency (for example, 4.5 GHz) having a length of electrical length λ / 2, so that it is small as shown in FIG. As shown in FIG. 8, the characteristic has a phase gradient that is gentler than that of the present embodiment at the resonance frequency, resulting in a low Q value.

  As described above, by using this embodiment for a resonator, strip line conductors having different electrical lengths are connected in parallel to form an LC parallel resonance circuit, and the strip line conductor is circular or fan-shaped to form a composite strip line. By using a conductor, the phase inclination can be increased, and a high Q value can be obtained. Further, a resonator having a higher degree of freedom can be obtained by combining a strip line and a microstrip line, and the Q value can be further increased by using a shield.

  In addition, the sector-shaped microstrip line conductor in the present embodiment includes a semicircle and a notched semicircle having an inner angle of 180 deg or more and less than 360 deg, in addition to an inner angle of less than 180 deg. Further, the numerical values and the like studied in FIGS. 7 and 8 are not limited to this, but are illustrated for explanation.

1 is a block diagram of a voltage controlled oscillator having inductive and capacitive microstrip line conductors according to an embodiment of the present invention. FIG. It is a block diagram of a voltage controlled oscillator having a composite microstrip line conductor according to an embodiment of the present invention. It is a block diagram which shows the layer structure of the resonator which concerns on embodiment of this invention. It is a block diagram explaining the relationship between two stripline conductors and each layer which concern on embodiment of this invention. It is explanatory drawing explaining the form of the composite microstrip line conductor which concerns on embodiment of this invention. It is explanatory drawing explaining the composite microstrip line conductor which concerns on embodiment of this invention, and the fan-shaped microstrip by a prior art. It is a characteristic view showing a phase characteristic with respect to the frequency of the voltage controlled oscillator according to the embodiment of the present invention. It is the characteristic view which showed the phase characteristic with respect to the frequency of the voltage controlled oscillator which concerns on a prior art. It is a block diagram of the voltage controlled oscillator which concerns on a prior art.

Explanation of symbols

  10,100 Resonator, 11,101 Variable voltage power supply, 12,102 Variable capacitance diode, 13 Dielectric, 14,104 First microstrip line conductor, 15 Ground conductor, 16 Second microstrip line conductor, 17 Composite microstrip Line conductor, 18 Phase adjustment microstrip line conductor, 19 Shield member, 20, 30, 200 Voltage controlled oscillator, 21 Feed terminal, 22, 112 Active element, 24, 114 Oscillation output terminal, 106 Open end microstrip line conductor, 108 Microstrip line conductor for phase adjustment.

Claims (8)

A strip in which a ground conductor is formed on both surfaces of a dielectric substrate, including two dielectrics, a stripline conductor sandwiched between the two dielectrics, and a power supply terminal connected to a power supply point of the stripline conductor In the line resonator,
The stripline conductor has two open stripline conductors with different electrical lengths connected in parallel.
A stripline resonator, wherein the open stripline conductor at the tip is a circular shape or a sector shape having a radius from a feeding point and a predetermined angle. In a microstripline resonator having a grounding conductor formed on one side of a dielectric and a microstripline conductor provided on the opposite side of the grounding conductor,
The microstrip line conductor has two open microstrip line conductors with different electrical lengths connected in parallel,
Tip open microstrip line conductor
A microstrip line resonator having a circular shape or a sector shape having a radius from a feeding point and a predetermined angle. The stripline resonator according to claim 1, wherein
The two tip open stripline conductors are two circles or sectors sharing one feed point, and combinations thereof,
An LC parallel resonant circuit that is inductive at an electrical length longer than λ / 4 and capacitive at an electrical length shorter than λ / 4 by connecting two open-ended open stripline conductors in parallel. Stripline resonator to be used. The microstrip line resonator according to claim 2,
The two open-ended microstrip line conductors are two circles or sectors that share one feed point, as well as combinations thereof,
An LC parallel resonant circuit that is inductive at an electrical length longer than λ / 4 and capacitive at an electrical length shorter than λ / 4 by connecting two tip open microstrip line conductors in parallel. A microstrip line resonator. The stripline resonator according to claim 3, wherein
One ground conductor has a through hole for passing a via, and another dielectric layer is laminated on the ground conductor,
A stripline resonator in which a tip open stripline conductor is fed from a feed point of the tip open stripline conductor through a through hole of one ground conductor and a via hole extending to the surface of another dielectric layer . The microstripline resonator according to claim 4, wherein
One ground conductor has a through hole for passing a via, and another dielectric layer is laminated on the ground conductor,
A microstrip in which a tip open microstrip line conductor is fed from a feed point of the tip open microstrip line conductor through a through hole of one ground conductor and a via hole extending to the surface of another dielectric layer Line resonator. The stripline resonator according to claim 5, wherein
A stripline resonator characterized in that two tip open stripline conductors are separately arranged in different dielectric layers. The microstripline resonator according to claim 6,
A microstrip line resonator comprising two tip open microstrip line conductors arranged separately on different dielectric layers.

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