JPH0897601A - High frequency diode switch - Google Patents

Abstract

PURPOSE: To miniaturize a high frequency diode switch by decreasing the length of an inductor line without losing features such as improvement of cut-off characteristic and reduction of loss. CONSTITUTION: A loss reduction LC circuit comprising an inductor L2 and a capacitor C2 is connected to an anode of a diode D switched to be conductive/ nonconductive, and a loss reduction LC circuit comprising an inductor L3 and a capacitor C3 is connected to a cathode of the diode D. A series circuit comprising a cut-off characteristic improvement inductor L5 and a DC blocking capacitor C5 is connected across the LC circuits. Thus, the inductor L5 is shared in common by the inductors L2, L3, resulting that a small inductance of the inductor L5 is enough.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency diode switch for switching a high frequency signal, for example, input / output in an antenna circuit thereof.

[0002]

2. Description of the Related Art Various types of high-frequency diode switches that are used for switching transmission / reception to / from an antenna of a wireless device are already known. For example, Japanese Unexamined Patent Publication No. 2-108301 discloses a switch circuit using a λ / 4 phase line (λ is a signal wavelength), and Japanese Utility Model Laid-Open No. 3-82902 discloses a switch using a PIN diode. It is disclosed.

Various techniques for improving the characteristics of such a diode switch in a high frequency band include:
There is one as shown in FIG. First, what is shown in FIG. 7A is to improve the cutoff characteristic. In parallel with the diode D which can be switched ON (conductive) and OFF (non-conductive) in accordance with the switching of input and output, Inductor L1
And a capacitor C1 connected in series. According to this, the cutoff characteristic is improved by performing parallel resonance by the capacitance component of the inductor L1 and the diode D. Incidentally, C1 is for DC cutting.

The one shown in FIG. 1B is for reducing the transmission loss, and the inductor L is provided at both ends of the diode D.
2 and a capacitor C2, and an LC circuit composed of an inductor L3 and a capacitor C3, respectively. This reduces the loss during transmission. The one shown in (C) of the same figure is a combination of the ones shown in (A) and (B) above.
The cutoff characteristics are improved and the loss is reduced.

[0005]

By the way, when an inductor is formed by a line element on a printed board or a multilayer board, a length corresponding to the value of the inductor is required. On the other hand, in the example of FIG. 5 (C), there are three inductors L1, L2, and L3, and in view of the circuit as a whole, the occupied area or the number of stacked layers inevitably increases. In order to reduce the size of parts, inductors L1 to L3
It is desirable to have a circuit configuration that requires a short line length.

The present invention focuses on the above points,
It is an object of the present invention to provide a high-frequency diode switch capable of shortening the liner length of the inductor and reducing the size of components without hindering the original functions of improving the cutoff characteristic and reducing the loss. is there.

[0007]

In order to achieve the above object, according to the present invention, the ON / OFF operation is performed corresponding to the switching operation.
An LC circuit for loss reduction by an inductor in series with the diode and a capacitor in parallel with the diode is connected to the anode side and the cathode side of the diode controlled by F, respectively. The cutoff characteristic improving inductor is connected in parallel with the diode so as to include these loss reducing LC circuits.

Therefore, the loss improving inductor is shared with the cutoff characteristic improving inductor, and the value thereof can be made small. Therefore, the line length is shortened and the area or volume is reduced. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS While there may be many embodiments of the present invention, a suitable number of embodiments will now be shown and described in detail. <Embodiment 1> First, Embodiment 1 will be described with reference to FIGS. FIG. 1 shows the configuration of the first embodiment, in which an inductor L2 is connected in series and a capacitor C2 is connected in parallel on the anode side of a diode D that can be switched ON and OFF in accordance with switching of signal input / output. Has been done. An inductor L3 is connected in series and a capacitor C3 is connected in parallel to the cathode side of the diode D. These LC circuits are for reducing the loss during transmission.

Next, in this embodiment, a series circuit of an inductor L5 and a capacitor C5 is connected in parallel with the entire LC circuit. By making parallel resonance by the capacitance component of the inductor L5 and the diode D, the cutoff characteristic is improved. The capacitor C5
Are connected for DC cut. in this way,
The parallel inductor and the capacitor for improving the cutoff characteristic are connected not outside the diode D but outside the LC circuit for improving the loss. Therefore, the inductors L2 and L3 are shared by both the parallel resonant circuit formed of L5 and C5 for improving the cutoff characteristic and the LC circuit for improving the loss.

Therefore, the value of the parallel-connected inductor L5 required to obtain the similar effect of improving the cutoff characteristic is smaller than that of the circuit of the background art shown in FIG. 5C. As a result, when the component is formed of a printed circuit board, a multilayer board, or the like, the line length of the inductor L5 is reduced, the area or volume is reduced, and the size can be reduced.

FIG. 2 shows a pattern of each layer of the component in which the first embodiment is constructed by the multilayer substrate. In the figure,
First, the ground pattern 12 is formed on the lowermost sheet 10. Reference numerals 14 and 16 are drawer portions. On the sheet 18 thereabove, one pattern C5A of the parallel resonance capacitor C5, the parallel resonance inductor pattern L5, and the lead portion 20 are continuously formed. On the sheet 22 thereabove, the other capacitor pattern C5B and the via hole 24 for forming the parallel resonance capacitor C5 corresponding to the capacitor pattern C5A are formed. 26 is a drawer part.

On the sheet 28 thereon, loss improving inductor patterns L2, L3 and via holes 30, 32 are formed, respectively. The via hole 30 is connected to the drawer portion 20 of the sheet 18 therebelow via the via hole 24 of the sheet 22 below. The via hole 32 is adapted to be connected to the pattern C5B of the sheet 22 therebelow.

On the sheet 34 thereon, component lands 36A, 36B for the diode D, via holes 38, 4 are provided.
0 is formed respectively. Beer holes 38, 40
Is the inductor pattern L2, L3 of the sheet 28 therebelow.
Are connected to each. Each of these sheets is laminated and pressure-bonded and then fired, and the diode D and side electrodes are attached to form a laminated composite component.

Next, the relationship between this laminated component and the circuit of FIG. 1 will be described. The lead-out portion 20 is the input end of FIG. 1, which is connected to the inductor pattern L5 on the one hand and the via hole 24, It is connected to the inverter pattern L2 through 30. Inductor pattern L5
Is connected to the capacitor C5 formed by the capacitor patterns C5A and C5B, and the lead-out portion 26 of this capacitor C5B serves as the output terminal of the circuit of FIG. The lead-out portion 26 is connected to the inductor pattern L3 through the via hole 32.

The inductor patterns L2 and L3 are connected to the diode D through via holes 38 and 40, respectively. Also, the capacitors C2 and C3 of the diode D are
It is formed as a stray capacitance between the component lands 36A and 36B and the ground pattern 12 in the lowermost layer.

By the way, attention is paid to the inductor patterns L2, L3, and L5 in such a component pattern. Figure 1
In the circuit of, the inductors L2 and L3 are, for example, several nH.
(2 to 3 nH), and the inductor L5 is, for example, about 10
It is nH. Therefore, the inductor pattern L5 is longer than the other inductor patterns L2 and L3, and is formed in a zigzag shape as shown in FIG. According to the present embodiment, since this can be short, the component area can be reduced.

Further, in this embodiment, since the line length of the inductor pattern L5 can be shortened, another pattern (capacitor pattern C5A in the illustrated example) can be formed on the same sheet. Therefore, the number of laminated sheets is reduced, and the volume of parts is reduced. Furthermore, these do not hinder the original functions of improving the cutoff characteristic and reducing the loss.

<Second Embodiment> Next, a second embodiment will be described with reference to FIG. In this embodiment, the first embodiment is applied to a switch for switching the supply of the output signal of the signal source SG to the load RL (for example, 50Ω). In the figure, the signal source SG is, for example, an internal resistance Rg.
Is 50 Ω, and one is connected to the ground and the other is connected to the input terminal T1 of the circuit of the first embodiment via the coupling capacitor C6. A series circuit of a signal cutting inductor L6 and a bypass capacitor C7 is connected between the input terminal T1 and the ground.

On the other hand, the output terminal T2 is connected to the load RL via the coupling capacitor C8 on the one hand, and the resistor R for limiting the direct current and the bypass capacitor C9 are connected between the output terminal T2 and the ground. . Further, the bypass capacitors C7 and C9 are connected to the changeover switches 50 and 52, respectively. These changeover switches 50 and 52 are for switching to the control DC power supplies V1 and V2, and are configured to operate in conjunction with each other.

Next, the overall operation of the second embodiment having the above configuration will be described. First, the state in which no signal is supplied to the load RL will be described. In this case, the changeover switch 50,
52 is a position opposite to the illustrated position. Therefore, the positive voltage of the control DC power supply V2 is equal to the DC current limiting resistance R,
It is applied to the cathode side of the diode D through the loss reducing inductor L3. As a result, the diode D is reverse-biased and turned off.

At this time, the current flowing from the control DC power supply V2 to the ground through the cutoff characteristic improving inductor L5 and the signal cutting inductor L6 is cut by the DC cutting capacitor C5.

Next, when supplying a signal to the load RL,
The changeover switches 50 and 52 are in the positions shown. Therefore, the positive voltage of the control DC power supply V1 is applied to the anode side of the diode D via the signal cutting inductor L6 and the loss reducing inductor L2. This causes diode D to be positively biased and O
The state becomes N. Therefore, the high frequency signal output from the signal source SG is supplied to the input terminal T1 via the coupling capacitor C6, and is supplied from the output terminal T2 to the load RL via the coupling capacitor C8 via the circuit of the first embodiment. To be done. The current flowing by the control DC power supply V1 at this time is limited by the resistor R.

<Third Embodiment> Next, a third embodiment will be described with reference to FIG. This embodiment is almost the same as the second embodiment.
The same as, but the inductor part is configured with a distributed constant circuit. That is, the loss reducing inductor L2 and the capacitor C2 on the anode side of the diode D are formed by the distributed constant circuit A2. Inductor L3 for reducing loss on the cathode side of diode D, capacitor C3
Is composed of a distributed constant circuit A3. The cutoff characteristic improving inductor L5 is composed of a distributed constant circuit A5. The signal cutting inductor L6 is composed of a distributed constant circuit A6.

The bypass capacitor C7 is a changeover switch 60 for changing over the control DC power supplies V1 and V2.
It is connected to the. No bypass capacitor is provided on the side of the current limiting resistor R. Set the changeover switch 60 to the power source V
When switched to the 1 side, the diode D is turned on and the high frequency signal output from the signal source SG is supplied to the load RL. To stop the signal supply, switch 60
To the power supply V2 side. Then, the diode D becomes O
It becomes FF, and the signal supply to the load RL is stopped.

<Other Embodiments> The present invention can be variously modified based on the above disclosure, and includes, for example, the following. (1) In the above embodiment, the present invention is applied to switching the supply of signals to a predetermined load, but is generally applicable to switching for high frequency signals, such as a transmission / reception changeover switch in an antenna of a wireless device. (2) The band of high-frequency signals to be handled is especially several hundred MHz
Up to several GHz are preferable, but not limited thereto. (3) The circuit configuration can be modified in various ways so as to achieve the same effect.

[0027]

As described above, according to the present invention, the overall value of the inductor for improving the cutoff characteristic and for reducing the loss is reduced. Has the effect of being reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a perspective view showing a pattern of each layer of a multilayer substrate which constitutes a circuit of Example 1.

FIG. 3 is a circuit diagram showing a configuration of a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a third embodiment of the present invention.

FIG. 5 is a circuit diagram showing an example of background art.

[Explanation of symbols]

 10, 18, 22, 28, 34 ... Sheet 12 ... Ground pattern 14, 16, 20, 26 ... Draw-out portion 24, 30, 32, 38, 40 ... Via hole 36A, 36B ... Component land 50, 52, 60 ... Changeover switch A2, A3, A5, A6 ... Distributed constant circuit C2, C3 ... Loss reduction capacitor C5 ... DC cut capacitor C6, C8 ... Coupling capacitor C7, C9 ... Bypass capacitor D ... Diode L2, L3 ... Loss reduction inductor L5 … Inductor for improving cutoff characteristics L6… Inductor for signal cutting R… Resistor for current limiting Rg… Internal resistance RL… Load resistance T1, T2… Terminals V1, V2… DC voltage source for control

Claims (2)

[Claims] 1. A loss reduction in which an inductor is connected in series with a diode and a capacitor is connected in parallel with the diode, which are provided on the anode side and the cathode side of a diode controlled to be turned on and off in response to a switching operation. High-frequency diode switch including an LC circuit for use in a circuit; an inductor for improving cutoff characteristics, which is connected in parallel with a diode so as to include these LC circuits for reducing loss. 2. A high frequency diode switch comprising the high frequency diode switch according to claim 1 in a distributed constant circuit formed of a multilayer substrate.