JPH06152241A - Voltage controlled oscillator - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a voltage-controlled oscillator that can obtain an oscillation output from which harmonic components and spurious components are removed and that is downsized. According to the present invention, a voltage-controlled oscillator in which a VCO section 10 having a resonance circuit section 11 composed of a stripline 21 and a BPF section 14 composed of a plurality of LC circuits are formed in a board body 2 of a multilayer circuit board. In addition, a plurality of dielectric layers capable of firing the substrate body 2 at a low temperature are laminated, and two dielectric layers 2b and 2c sandwiching a strip line 21 made of a silver-based or copper-based conductor are provided as silver-based or copper-based. The resonance circuit section 11 is arranged so as to be sandwiched between two earth electrode layers 22 and 23 made of a system conductor, and a predetermined capacitance is provided between the spiral coils 25 and 26 and the earth electrode layers 22 and 23 between the dielectric layers 2b and 2c. The generated capacitor electrode patterns 27 and 28 were formed respectively, and a part of the BPF part 14 was arranged inside the substrate body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage-controlled oscillation circuit section (hereinafter
VCO section) and bandpass filter circuit section (hereinafter,
BPF section) is formed on a multilayer circuit board.

[0002]

2. Description of the Related Art A voltage-controlled oscillator, which is widely used in mobile communication equipment and the like, has been used as a part of the spar heterodyne type transmission / reception system (dotted line portion in the figure).

For example, in the receiving system, the antenna (A
The radio signal detected from NT is a high frequency amplifier (RF
The signal of the frequency of the predetermined channel, which is amplified by (amplification), is selected by a bandpass filter (BPF). This BPF
The signal passing through is 800M for a mobile phone, for example.
It is a high frequency around Hz. In order to convert this into sound, it was put into an intermediate frequency by a mixer (MIX), amplified by an intermediate amplifier (IF amplification), and demodulated by a demodulator (DET).

At this time, in order to convert the frequency of the intermediate frequency, the signal of the local oscillation from the voltage controlled oscillation circuit (VCO section) is input to MIX. The signal of this voltage controlled oscillator circuit has harmonic components and spurious components of the oscillation frequency removed.
Alternatively, it is important that it is sufficiently damped.

However, if the voltage-controlled oscillator having the voltage-controlled oscillator circuit is downsized, the harmonic components and spurious components cannot be sufficiently removed. For this reason, a bandpass filter (BPF part) is connected to the output stage of the voltage controlled oscillator circuit to remove the harmonic components and spurious components.

[0006]

However, even if the BPF section is to be connected to the VCO section, a plurality of LC resonance circuits and a plurality of dielectric resonators constituting the BPF section are formed on a single dielectric substrate. Therefore, the size of the substrate becomes large.

The present invention has been devised in view of the above-mentioned problems, and provides a voltage-controlled oscillator in which a local oscillation signal from which a harmonic component and a spurious component are removed can be obtained and which is downsized. Especially.

[0008]

The present invention is a voltage controlled oscillator in which a voltage controlled oscillator circuit section including a resonance circuit section and a band pass filter circuit section including an LC circuit are formed on a multilayer circuit board. The multi-layer circuit board is formed by laminating a plurality of dielectric layers that can be fired at a low temperature, and the resonance circuit section is formed of a silver-based or copper-based strip between two ground electrode layers made of a silver-based or copper-based conductor. By forming a line, and by arranging the LC circuit of the bandpass filter circuit portion with respect to one of the earth electrode layers, a coil to which a capacitor electrode is connected with a dielectric layer interposed therebetween. It is a voltage-controlled oscillator formed.

[0009]

According to the voltage controlled oscillator of the present invention, the resonant circuit section of the VCO section, particularly the strip line, is formed in the multilayer circuit board formed by laminating a plurality of dielectric layers that can be fired at a low temperature. , The LC resonance circuit of the BPF section is arranged. Therefore, since the substrate is composed of the dielectric layer that can be fired at a low temperature, each pattern of L (inductance component) -C (capacitance component) of the strip line and the BPF part is composed of a silver-based or copper-based conductor, The characteristics are improved.

Further, since it is not necessary to form the strip line of the resonance circuit portion having a large occupied area on the surface of the substrate body, the miniaturization of the entire substrate, that is, the oscillator can be achieved.

Further, since the capacitor electrode pattern connected to the coil for generating the inductance component of the BPF section is arranged inside the substrate, the miniaturization of the entire substrate can be achieved.

Moreover, since a capacitance component is obtained between the capacitor electrode pattern and one ground electrode layer which sandwiches the strip line, it is not necessary to form the other capacitor electrode, and the number of laminated layers can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A voltage controlled oscillator according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram of the voltage controlled oscillator, and FIG. 2 is an exploded perspective view of the voltage controlled oscillator.

The voltage controlled oscillator includes a resonance circuit section 11 and
VC composed of the negative resistance circuit section 12 and the amplification circuit section 13
BPF section 1 including O section 10 and a plurality of LC resonance circuit sections
4 and.

As a basic operation, the strip line SL1 of the resonance circuit section 11 of the VCO section 10 and the varicap diode DV are connected in parallel, and a control voltage for controlling the oscillation frequency is input to the VT terminal. As a result, the capacitance of the varicap diode DV is changed to cooperate with the strip line SL1 to cause resonance at a predetermined frequency. This signal is output by the negative resistance circuit section 12 including the transistor Q _{1 and the} like and the amplification circuit section 13 including the amplifying transistor Q _{2 and the} like to the BPF section 14 as an oscillation signal of a predetermined frequency.

Further, this oscillation output is sent to the BPF section 14
Passes only a predetermined frequency band to remove or attenuate harmonic components and spurious components other than the predetermined oscillation frequency.

As a result, a stable local oscillation signal can be supplied to the MIX in the super-heterodyne system of mobile band communication.

The voltage controlled oscillator (dotted line portion in FIG. 3) shown in FIG. 1 is constituted by a predetermined circuit on the inside and main surface of the main body 2 of the multilayer circuit board as shown in FIG. 30 is covered and comprised.

The multi-layered substrate body 2 is composed of, for example, three dielectric layers 2a to 2c. Inside the substrate body 2, the strip line (SL1) 21 of the resonance circuit section 11 and the first layer are provided.
L-C resonance circuit constituting the ground electrode layer 22, the via hole 24, further a BPF unit 14, in fact, the inductance L _1, L ₂ become spiral coil patterns 25 and 26, a capacitor C12, C13 generated One capacitor electrode pattern 27, 28 is formed.

A surface wiring pattern 29 is formed on one main surface of the substrate body 2, and a second ground electrode layer 23 is formed on the other main surface of the substrate body 2.

The surface wiring pattern 29 formed on the one main surface of the substrate body 2 has various electronic components, varicap diodes DV, and chips in order to configure circuits other than those formed inside the substrate body 2. A capacitor C, a chip resistor R, a transistor Tr, etc. are mounted.

The substrate body 2 has a predetermined dielectric constant and is a glass-ceramic material that can be fired at a low temperature, such as SiO 2.
A substrate material in which a glass component such as ₂ , Al ₂ O ₃ , B ₂ O ₃ , and ZnO is mixed with an inorganic filler such as alumina powder is used. The component ratio is such that the glass component is 20 to 80 wt% and the inorganic filler such as alumina powder is 30 to 70 wt%, and such a substrate material is made into a green sheet, and a plurality of layers are laminated and fired. However, the firing temperature is about 800-10
It is fired at a low temperature of 00 ° C.

The method for manufacturing the substrate body 2 is as follows. A strip line 21, a ground electrode layer 22, and a spiral coil pattern are formed on each green sheet to be the above-mentioned dielectric layers 2a to 2c, for example, by paste of a silver-based conductor material. 25,
26 and capacitor electrode patterns 27 and 28 are formed by printing. Specifically, each green sheet is punched so as to achieve a predetermined connection to form a through hole in which the via hole 24 is formed, and the through hole is filled with, for example, a silver-based conductor paste. Also, the dielectric layer 2b
The ground electrode layer 22 is formed on substantially the entire surface of the green sheet except for the periphery of the via hole 24. Further, the strip line 21 and the coil patterns 25 and 26, and the capacitor electrode patterns 27 and 28 having a predetermined shape are formed on the green sheet which will be the dielectric layer 2c.

After that, the dielectric layer 2 is considered in consideration of the stacking order.
a to 2c are laminated and integrated, and fired at 900 ° C. in an oxidizing atmosphere. As a result, via holes 24 extending from the strip line 21 and the ground electrode layer 22 are exposed on the surfaces of the dielectric layers 2a and 2c located on both outermost surfaces of the substrate body 2.

Next, a surface wiring pattern 29 is printed and fired on the one main surface of the fired substrate body 1 with a copper-based conductor. Further, the ground electrode layer 23 is printed and fired on the other main surface of the substrate body 1 with a copper-based conductor. At this time, as a firing condition, the firing is performed in a non-oxidizing atmosphere at a temperature lower than 780 ° C. If the surface wiring pattern 29 and the earth electrode layer 23 are made of silver (silver or a silver alloy such as silver-palladium), the material is fired at about 900 ° C. in an oxidizing atmosphere.

On the surface wiring pattern 29 formed on the one main surface of the substrate body 2, a part of the resonance circuit section 11, the negative resistance circuit section 12, the amplification circuit section 13, the BPF section 1 shown in FIG.
The varicap diode DV, the chip capacitor C, the resistor R, the transistor Tr, and the like, which are a part of 4, are soldered. In FIG. 2, only the input / output capacitor of the BPF unit 14 and the chip capacitor C that serves as a coupling capacitor of the LC resonance circuit are shown, but in addition, the strip line 21 of the resonance circuit unit 11 of the VCO unit 10 Except for the chip capacitor C and the varicap diode DV, the negative resistance part 12, the chip capacitor C forming the amplifier circuit part 13, the resistor R, the transistor Tr, and the like are arranged.

The resistor R may be formed of a thick film resistor film other than the chip resistor. In this case, when the substrate body 2 is formed, it is simultaneously formed on one main surface of the substrate body 2. Specifically, the surface wiring pattern 29
In the process of forming, a resistor material paste made of lanthanum hexaboride (suitable for firing in a non-oxidizing atmosphere) or ruthenium oxide (suitable for firing in an oxidizing atmosphere) is printed and fired. It is formed.

With the above configuration, the strip line 21
Is sandwiched between the dielectric layers 2b and 2c, and the dielectric layers 2b and 2c are sandwiched between the first ground electrode layer 22 and the second ground electrode layer 23. As a result, the stripline SL1 of the resonance circuit unit 11 shown in FIG. 1 is configured. Further, two coil patterns 25 and 26 formed between the dielectric layers 2b and 2c and capacitor electrode patterns 27 and 28 are configured, and one end of the coil pattern 25 and the capacitor electrode pattern 27 are coil patterns. One end 26 and the capacitor electrode pattern 28 are connected to each other. Further, one end portions of the connected coil patterns 25 and 26 are connected to the wiring pattern 29 on the surface of the dielectric layer 2a via the via holes 24, respectively, and the other end portions of the coil patterns 25 and 26 are connected to each other. , The ground electrode layers 22 and 23 on the surfaces of the dielectric layers 2b and 2c
To the via hole 24. Furthermore, the capacitor electrode patterns 27 and 28 face the ground electrode layers 22 and 23 via the dielectric layers 2b and 2c, respectively, and a capacitance component C proportional to the facing area is formed. Thereby, the inductance component (L) of the BPF portion 14 is caused by the coil patterns 25 and 26, and the inductance component B at the capacitor electrode patterns 27 and 28 and the ground electrode layers 22 and 23.
The capacitance component (C) of the PF unit 14 is formed and connected to each other to form two LC resonance circuits.

The three chip capacitors C11, C14, CC15 formed on the surface of the substrate body 2 are the input / output capacitors C11, C15 of the BPF section 14 and two L- capacitors.
A coupling capacitor C14 for coupling the C resonance circuit.
Further, the input / output capacitors C11, C15 and the coupling capacitor C14 may be formed inside the substrate body 2 similarly to the C component of the LC resonance circuit described above, and further, depending on the band characteristic. Two or more L-C resonant circuits may be formed.

In the above-mentioned oscillator, since the BPF section 14 connected to the output stage of the VCO section 10 can be constructed by one multilayer circuit board, the harmonic component and the spurious component can be effectively removed, and the oscillator is easy to handle. Becomes

Further, the strip line 21 constituting the resonance circuit portion 11 and the ground electrode layers 22 and 23 arranged so as to sandwich the strip line 21 are made of a silver-based or copper-based conductive material excellent in high frequency characteristics, Since it is silver-based or copper-based, and a part of the silver-based or copper-based substrate material is integrally formed at the same time as the substrate material that can be fired at a low temperature, and is disposed inside the substrate body 2, the manufacturing process is performed with good electrical characteristics. It is possible to simplify and downsize the entire oscillator.

Furthermore, the capacitor electrode patterns 27, 26 are arranged so that the coil patterns 25, 26 of the BPF section 14 and one of the capacitor electrode patterns 27, 28 connected to the coil patterns 25, 26 form a capacitance component inside the substrate body 2.
Since 28 is disposed so as to face the above-mentioned ground electrode layers 22 and 213, the coil patterns 25 and 26 and the capacitor electrode patterns 27 and 28 which require a relatively large area can be eliminated on the surface of the substrate body 2. Therefore, the oscillator can be further downsized.

Although the coil patterns 25 and 26 are shown in a spiral shape, other strip line type coil patterns may be used. In this way, if it is a spiral type or stripline type, it can be formed between one layer sandwiched by two dielectric layers, and a coil is formed across multiple layers like a helical type. Therefore, the manufacturing process is simplified and reliability is improved.

In the above-mentioned embodiment, the second ground electrode layer 23 is formed so as to be exposed on the back surface side of the substrate body 2. However, a dielectric layer may be further superimposed on this ground electrode layer 23. , And a predetermined circuit on the back surface side, for example, the PLL circuit or the low pass filter (LPF) shown in FIG. 3 may be formed on the dielectric layer side. These circuits operate digitally and are operated at a relatively low frequency. With this configuration, the noise of the high frequency component generated from the high frequency operation circuit on the front surface side of the substrate body is The circuit is interrupted by the ground electrode layers 22 and 23 inside the substrate body 2 so that the circuits can operate stably.

[0036]

As described above, according to the present invention, it is possible to obtain a oscillating output from which harmonic components and spurious components have been removed, and to provide a miniaturized voltage controlled oscillator.

[Brief description of drawings]

FIG. 1 shows an oscillator circuit diagram of a voltage controlled oscillator of the present invention.

FIG. 2 is an exploded perspective view of the voltage controlled oscillator of the present invention.

FIG. 3 is a block circuit diagram of a typical superheterodyne system.

[Simple explanation of symbols]

 10 ...- Voltage control type oscillation circuit unit 11 ... Resonance circuit unit 12 ... Negative resistance circuit unit 13 ... Amplification circuit unit 14 ... Handpass filter unit 2 ...・ Substrate body 21 ・ ・ ・ ・ Strip lines 22, 23 ・ ・ ・ Earth electrode layer 24 ・ ・ ・ ・ Via holes 25, 26 ・ ・ ・ Coil pattern 27, 28 ・ ・ ・ Capacitor electrode pattern 29 ・ ・ ・・ Surface wiring pattern 30 ・ ・ ・ Shield case DV ・ ・ ・ Varicap diode C ・ ・ ・ ・ Capacitor R ・ ・ ・ ・ Resistance

Claims (1)

[Claims] 1. A voltage-controlled oscillator in which a voltage-controlled oscillation circuit unit including a resonance circuit unit and a bandpass filter circuit unit including an LC circuit are formed on a multilayer circuit board, wherein the multilayer circuit board is at a low temperature. A plurality of fireable dielectric layers are formed by stacking, and the resonance circuit section is formed by arranging a silver-based or copper-based strip line between two ground electrode layers made of a silver-based or copper-based conductor, The voltage control is characterized in that the LC circuit of the bandpass filter circuit unit is formed by arranging a coil to which one of the ground electrode layers is connected with a capacitor electrode with a dielectric layer interposed therebetween. Type oscillator.