Voltage controlled oscillator small in reduction of inductance and Q

Abstract

There is provided a voltage controlled oscillator having a favorable shield characteristic between a strip line and a wiring pattern and being small in reduction of inductance and Q. The voltage controlled oscillator comprises a circuit board having a laminate of a plurality of insulating plates (2), a wiring pattern (3) formed on a surface of the circuit board (1), an electronic part (8) mounted on the surface of the circuit board (1), a resonance strip line (5) provided on an inner layer of the circuit board (1), and a ground pattern (7) formed on an inner layer of the circuit board (1) which is disposed between the wiring pattern (3) and the strip line (5). Further, an opening (7a) in the ground pattern (7) faces the vicinity including a portion having a high current density in the strip line (5). Thus, reductions of inductance and Q are small. In addition, a portion of the strip line (5) is shielded by means of the ground pattern (7) with respect to the wiring pattern (3). As a result, a voltage controlled oscillator having a favorable shield characteristic can be obtained.

Description

technical field [0001] The present invention relates to a voltage-controlled oscillator suitable for portable telephones and the like. Background technique [0002] First, the drawings of the conventional voltage-controlled oscillator will be described. FIG. 13 is an exploded perspective view of the conventional voltage-controlled oscillator, and FIG. 14 is a cross-sectional view of main parts of the conventional voltage-controlled oscillator. [0003] Next, the structure of the conventional voltage-controlled oscillator will be described with reference to FIGS. 13 and 14. The circuit board 51 is formed by laminating a plurality of thin insulating plates 52, and the surface 51a of the circuit board 51 is provided with conductive patterns. The wiring pattern 53 formed by the circuit board 51 and the ground conductor 54 formed by the conductive pattern are provided on the entire back surface 51b of the circuit board 51 . [0004] In addition, the inner layer of the circuit bo...

AI Technical Summary

Problems solved by technology

[0009] However, in such a conventional voltage-controlled oscillator, the ground pattern 56 is not provided on the surface side of the strip line 55, and the inductance and Q However, since the entire surface of the stripline 55 faces the surface 51a of the circuit board 51 due to the conductor cutout portion 56a, the shielding characteristic between the stripline 55 and the wiring pattern 53 deteriorates.

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