JPH0424641Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electronic circuit device used in an electronic device, such as a wireless device, in which electronic circuits of different frequency bands coexist.

[Technical background of the invention and its problems] Fulters and voltage-controlled oscillators for radio equipment, which were conventionally designed using dielectric resonators, etc., can have a smaller circuit configuration in an appropriate frequency band, but if If an attempt is made to construct a circuit that operates at a frequency lower than the above frequency, the board size will increase accordingly, and the circuit elements will become larger, making it impossible to satisfy the demand for miniaturization of the entire circuit.

Therefore, it is conceivable to incorporate strip lines on the board in order to miniaturize the circuit configuration.
Unlike a dielectric resonator, a stripline allows for flexible board dimensions because the bending arc can be set arbitrarily, but the entire length must be a constant length. There are limits to miniaturization.

In order to equivalently shorten such strip lines and reduce the size of the entire substrate, it is effective to use a substrate with a high dielectric constant.

However, when a high dielectric constant substrate is used, there is a problem in that the stray capacitance between the circuit pattern formed on the substrate and the ground increases, making it difficult to match the impedance of the entire electronic circuit.

[Purpose of the invention] The present invention was made in view of the above circumstances, and even when electronic circuits ranging from low frequency bands to high frequency bands are mixed, the overall shape of the circuit can be made smaller and thinner. It is an object of the present invention to provide an electronic circuit device in which overall impedance matching can be easily achieved.

[Summary of the invention] In order to achieve the above object, the present invention has a structure in which a first dielectric substrate having a high dielectric constant and a second dielectric substrate having a low dielectric constant are laminated and bonded,
An electronic circuit including a resonant circuit that operates in a low frequency band is formed on the surface of the first dielectric substrate, and an electronic circuit including a voltage controlled oscillator that operates in a high frequency band is formed on the back surface of the second dielectric substrate. This feature allows the device to be made smaller and thinner, and makes it easier to match the impedance of the entire circuit.

[Example of idea] Embodiments of the present invention will be described in detail below.

The electronic circuit device shown in the drawing includes a first substrate (dielectric substrate) made of ceramics having a high dielectric constant ε _H.
1 and a second substrate (dielectric substrate) 2 made of ceramics, Teflon, or epoxy resin having a dielectric constant ε _L lower than that of the first substrate 1, and the surface of the first substrate 1 is bonded. On the circuit pattern 3a formed in
a, 6a, 7a and the coil 8 are connected by soldering or the like, and on the circuit pattern 3b formed on the back surface of the second substrate 2, there is an electronic circuit (for example, a filter, a voltage controlled oscillator, etc.) that operates in a high frequency band. It is constructed by connecting chip parts 4b, 5b, 6b, and 7b constituting each other by soldering or the like.

The circuit pattern 3a of the first substrate 1 and the circuit pattern 3b of the second substrate 2 are formed on both substrates 1,
2 are electrically connected by through holes 9a and 9b provided through them to form a distributed constant circuit, whereby both electronic circuits provided on the first substrate 1 and the second substrate 2, respectively. are designed to work together as two sides of the same coin.

The relationship between the dielectric constant ε _H of the first substrate 1 and the dielectric constant ε _L of the second substrate 2 is set to be ε _H =9ε _L , for example.

Next, the operating frequency of the electronic circuit in which the function of the electronic circuit device having the above configuration is incorporated on the first substrate 1 is determined.
An example will be explained in which the operating frequency of the electronic circuit incorporated on the second substrate 2 is 400 MHz and 900 MHz.

When the electronic circuit on the first substrate operates at a frequency of 400 MHz, the dielectric constant ε _H of the first substrate 1 is high as described above, so it is equivalent to the case where a substrate with a dielectric constant ε _L is used. In this case, since the operating frequency is relatively low at 400 MHz, the circuit pattern 3a on the first substrate 1 and the ground of this device can be reduced. The stray capacitance between them can be increased, and the input impedance and output impedance of this electronic circuit are also reduced accordingly.

On the other hand, when the electronic circuit on the second substrate 2 operates at a frequency of 900MHz, the dielectric constant ε _L of the second substrate 2
is smaller than the dielectric constant ε _H of the first substrate 1, so the stray capacitance is small, and even if the frequency on the second substrate 2 is high, the effect of the stray capacitance between the circuit pattern 3b and the ground can be reduced It can be made almost equivalent to the case.

As a result, impedance matching between both electronic circuits can be easily achieved.

Additionally, if the dielectric constant of the substrate is increased in order to reduce the size of the substrate, the precision of the circuit pattern becomes a problem.
In the electronic circuit device of this embodiment, an electronic circuit that operates at a low frequency is incorporated into the first substrate 1 having a high dielectric constant ε _H , so the accuracy of the circuit pattern 3a of the first substrate 1 is not a particular problem. .

In this way, according to this electronic circuit device, two electronic circuits that operate at different frequencies are incorporated on the first and second substrates 1 and 2 to form a distributed constant circuit. By appropriately changing the values of dielectric constants ε _H and ε _L , it is possible to downsize the first substrate 1 into which a low frequency electronic circuit is incorporated, and to make the dimensions of both substrates 1 and 2 the same. It is also possible to have a combination of arbitrary sizes.

In addition, by using a material with a high dielectric constant ε _H as the first substrate 1, a circuit element that can operate at a low frequency without changing the size (height, width, etc.) of the circuit element (chip component) itself can be used. It is possible,
The thickness of the entire device can be kept within a certain range.

It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made within the scope of the invention.

For example, by appropriately changing the thickness of the first and second substrates 1 and 2, it is possible to reduce stray capacitance due to the difference in thickness in addition to the difference in dielectric constant, and further improve impedance matching. can.

Further, in the above-described embodiment, the case where an electronic circuit using chip parts is incorporated on the first and second substrates is explained, but it can be similarly implemented as an electronic circuit formed by patterning these, and in this case, the device It becomes possible to reduce the thickness of the

[Effects of the invention] According to the invention described in detail above, by utilizing the difference in permittivity of a plurality of laminated and bonded substrates, it is possible to miniaturize the entire electronic circuit with a wide frequency band, and to reduce the impedance. It is possible to provide an electronic circuit device that is easy to match.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of the present invention. 1...First substrate, 2...Second substrate, 3a,
3b...Circuit pattern, 4a, 4b, 5a, 5
b, 6a, 6b, 7a, 7b...chip parts, 8
...Coil, 9a, 9b...Through hole.

Claims (1)

[Scope of utility model registration request] A first dielectric substrate having a high dielectric constant and a second dielectric substrate having a low dielectric constant are laminated and bonded, and a surface of the first dielectric substrate includes a resonant circuit that operates in a low frequency band. An electronic circuit is formed,
An electronic circuit device characterized in that an electronic circuit including a voltage controlled oscillator that operates in a high frequency band is formed on the back surface of the second dielectric substrate.