JPS63227104A - Balance type mixer - Google Patents

Abstract

PURPOSE:To facilitate the confirmation, etc., of a diode, and to raise the degree of freedom of a circuit design by providing a microstrip line being an important part of a mixer circuit, and the diode, and providing only a slot line on the reverse side. CONSTITUTION:On the surface of a dielectric substrate 14, a first microstrip line 2 which becomes an input/output terminal of a local oscillating signal, second and third microstrip lines 3, 4 which branch therefrom, and also, connected in the other end, and a fourth microstrip line 11 placed separately, which becomes an input/output terminal of a high frequency signal are provided. Also, to a part of the lines 3, 4, one electrode of mixer diodes 5, 6 of a reverse direction is connected, and the other electrode of them is connected to a ground conductor 13 provided on the reverse side of the substrate 14 through ground patterns 7, 8. Moreover, on the reverse side of the substrate 14, a lambda/4 wavelength other end short circuit slot line 9 and a slot line 10 connected to said lines are provided, and important parts can be confirmed by only the surface of the substrate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a small microwave integrated balanced mixer that is used in microwave communication equipment and the like and is composed of a microstrip line and a slot line.

[Conventional technology]

Conventionally, balanced mixers constructed using microstrip lines require branch-line hybrid or rough-trace hybrid circuits, which has the disadvantage of increasing the overall size of the circuit. Therefore, a miniaturized balanced mixer is realized by combining a microstrip line and a slot line. Examples of this type of balanced mixer are shown in FIGS. 6 and 7.

6 is a plan view, and FIG. 7 is a sectional view thereof. In the figure, a high frequency (RF) signal input from a terminal 33 via a microstrip line 32 formed on the surface of a dielectric substrate 31 is Slot line 3 formed on the back side of the board
4 and applied to mixer diodes 35 and 36 in opposite phases.

On the other hand, the local oscillator (LD) signal inputted from the microstrip line 37 is transmitted to the slot lines 39 and 4 by a microstrip line 38 with a length of λ/4 with one end open.
0 and applied to mixer diodes 35 and 36 in phase. At this time, the mixer diodes are in opposite directions on the slot lines 39 and 40, so the generated intermediate frequency (
The IF) signal passes through the microstrip line 37 and is output from the terminal 41. Note that 42 is a grounding pattern.

[Problem that the invention seeks to solve]

By the way, since a microstrip line is the main transmission path in a typical microwave integrated circuit, in the conventional balanced mixer described above, the slot line and mixer diode are arranged on the back surface of the dielectric substrate. For this reason, it is not possible to visually check the status of the diode installation after this mixer is installed in the equipment, and if any malfunction occurs, the board must be removed from the equipment and checked each time. . In addition, in electrical adjustment, it is often necessary to adjust both the slot line side and the microstrip line side, resulting in poor workability.

Furthermore, in the case of a microstrip line, since the back side is usually a ground conductor, a structure is adopted in which the board is soldered to the conductor subcarrier or the board is directly attached to the housing of the device.

However, in the conventional structure described above, where the slot line is on the back side, it is necessary to separate the slot line to some extent from the conductor on the back side in order to perform signal transmission. It is necessary to remove a large area of the conductor from the housing, and the surface for mounting the board is reduced, which may cause unstable electrical contact or cause resonance in the removed portion.

An object of the present invention is to provide a balanced mixer that can improve workability and ensure stability of operation.

Means for Solving Problem c] The balanced mixer of the present invention includes a first microstrip line into which either an intermediate frequency signal or a single high frequency signal is input to one end, and other parts of this line. A second . A third microstrip line and a fourth line separated from these lines as input/output terminals for other signals.
A microstrip line is provided on the front surface of the substrate, while a slot on the back surface is perpendicular to the connection position, one end of which is electromagnetically open at this connection, and the other end of which is converted into the fourth microstrip line. and the second line. Two diodes, one electrode of which is connected to the third microstrip line and the other electrode connected to a metal pattern that is electromagnetically connected, are disposed on the surface of the substrate.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

(First Embodiment) FIG. 1 is a plan view of a first embodiment of the present invention, and FIG. 2 is a sectional view thereof.

In this figure, the surface of the dielectric substrate 14 has a first microstrip line 2 whose one end serves as an input/output terminal for either an intermediate frequency signal or a single high frequency signal, here a local oscillation signal. , this first microstrip line 2
a second . branched from and connected at the other end. A third microstrip line 3.4 and a fourth microstrip line 11 spaced apart from these lines are formed as input/output terminals for other signals, here high frequency signals. Said 2nd. Mixer diodes 5.6 are connected in opposite directions to a part of each third microstrip line 3.4. The mixer diodes 5 and 6 have one electrode connected to each microstrip line 3 and 4, and the other electrode soldered to a ground pattern 7.8 connected to a ground conductor 13, which will be described later, through a through hole, respectively. and is electromagnetically shorted.

Further, on the back surface of the dielectric substrate 14, the second and third
perpendicular to the connection of microstri-knob line 2.3,
One end is electromagnetically open to this connection part, and the other end forms a λ/4 wavelength other-end short-circuited slot line 9 and a slot line 10 which are converted into the fourth microstrip line 11. Further, a ground conductor 13 is formed on the back surface. Note that 1° 12 is each terminal of the microstrip lines 2 and 11.

In this configuration, an LO multiplied signal inputted from terminal 1 via microstrip line 2 is applied in phase to mixer diodes 5 and 6 via microstrip lines 3 and 4. On the other hand, the RF multiplied signal inputted from the terminal 12 via the microstrip line 1 is converted to the slot line 10 on the back side of the board 14, and then sent to the connection part between the microstrip lines 3 and 4, which has a length of λ/4. It is opened by the short-circuited slot line 9, and is converted to the microstrip lines 3 and 4 in reverse phase.

Therefore, it is applied to the RF double signal mixer diodes 5 and 6 in opposite phases. At this time, since the branch point from the microstrip line 2 to the microstrip lines 3 and 4 is an equivalent short-circuit point for the RF multiplied signal, the distance between this branch point and the mixer diodes 5 and 6 is calculated as the RF multiplied signal λN/
4 (N=1°3.5...), the RF multiplied signal will be most efficiently applied to each diode.

Here, since the mixer diodes 5 and 6 are oriented in opposite directions to the microstrip lines 3 and 4, respectively, the IF multiplied signal is outputted from the terminal 1 through the microstrip line 2.

In this way, in a balanced mixer with this configuration, the main part of the circuit can be composed of the microstrip line and the diode provided on the surface of the board, and the electrical adjustment and installation of the diode etc. can be done by visual inspection of the condition etc. Improves workability. In addition, it is only necessary to provide the slot lines 9 and 10 on the back side, and there is only a small amount of removed part on the housing side opposite to this, and since the contact area between the board and the housing can be large, the electrical and mechanical is also stable.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention, in which the same parts as in the first embodiment are given the same reference numerals and their explanations will be omitted.

In the first embodiment, the other electrodes of the mixer diodes 5 and 6 were connected to the ground pattern 7°8 having a through hole, but in this embodiment, a low impedance close to a short circuit in the microwave band is established in the electromagnetic field. Metal pattern shown 15.16
, and the patterns are connected by a metal wire 17.

According to this configuration, unlike the first embodiment, there is no need for through-hole construction to drill holes in the board, so the configuration can be made at a lower cost, and performance deterioration due to the influence of parasitic reactance in the through-hole section can be avoided in high frequency bands. It is more useful because it can be avoided.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention, and similarly, 'Identical parts are given the same reference numerals.

In this embodiment, the RF choke circuit 18 is connected to the mixer diode 5.6 and the microstrip line 2, respectively.
．． 19.20 is connected. Here, the RF choke circuits 18 and 19 are configured to simultaneously apply microwave short-circuit conditions to the diodes 5 and 6.

In such a configuration, by individually applying a DC bias between terminals 21 and 23 or between terminals 22 and 23, the operating points of diodes 5 and 6 can be adjusted independently. It becomes possible to improve unbalance caused by variations in characteristics. Also, if you apply a pulse signal instead of DC bias,
It is clear that it can also be operated as a modulator.

(Fourth Embodiment) FIG. 5 is an example of a transmission frequency conversion circuit using the balanced mixer of the present invention. In addition, in the figure, 25.27
is a band pass filter, 28 is a low pass filter, and 24
, 26 and 29 are respective terminals.

Here, the IP multiplied signal input from the terminal 29 via the low-pass filter 28 is applied in phase to the mixer diodes 5A and 6A through the microstrip line 2 and 3.4.

On the other hand, the LO flaw signal inputted from the terminal 26 passes through the bandpass filter 27 and is converted to the slot line 10 at the point P.
It is applied to the diodes 5A and 6A in reverse phase. At this time, unlike the previous embodiments, the diodes 5A and 6A are attached in the same direction with respect to the microstrip lines 3 and 4, so the generated RF multiplied signal passes through the slot line IO and connects to the microstrip line at point P. After being converted into , it passes through a bandpass filter 25 and is output from a terminal 24 .

In this way, in the mixer of this embodiment, the input/output terminals for each signal can be selected depending on the mounting direction of the mixer diode, and can be adapted to various designs.

〔Effect of the invention〕

As explained above, the present invention is composed of the first to fourth microstrip lines provided on the surface of the substrate, the slot lines provided on the back surface of the substrate, and the diodes provided on the surface of the substrate. It is possible to improve workability by making it easier to confirm the above, and also to facilitate mounting on a housing, which is extremely useful in terms of freedom in circuit design.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a first embodiment of the balanced mixer of the present invention, FIG. 2 is a sectional view of the balanced mixer of FIG. 1, and FIG.
The figure is a plan view of the balanced mixer of the second embodiment, FIG. 4 is a plan view of the balanced mixer of the third embodiment, and FIG. 5 is a transmission frequency conversion circuit using the balanced mixer of the fourth embodiment. 6 is a plan view of a conventional balanced mixer, and FIG. 7 is a sectional view of the balanced mixer shown in FIG. 6. 1...Terminal, 2...First microstrip line, 3.4...Second. third microstrip line,
5.6.5A, 6A... mixer diode, 7.8.
...Grounding pattern, 9.10...Slot line, 11
...Fourth microstrip line, 12...Terminal, 13...Grounding conductor, 14...Substrate, 15.16.
...Metal pattern, 17...Wire, 18.19.2
0...RF choke circuit, 21,22.23...Terminal, 24°26.29...Terminal, 25.27.28.
...filter. 31... Dielectric substrate, 32... Microstrip line, 33... Terminal, 34... Slot line, 35
, 36... mixer diode, 37... microstrip line, 38... microstrip line, 3
9゜40...Slot line, 41...Terminal, 42...
...Grounding pattern. Figure 1 Figure 4 Figure 5

Claims (2)

[Claims] (1) A first microstrip line into which one of an intermediate frequency signal, a high frequency signal, or a local signal is input at one end, and a position branched from the other end of this line and whose other end corresponds to this branch position. A second and third microstrip line interconnected with each other and a fourth microstrip line separated from these lines as input/output terminals for other signals are provided on the front surface of the board, while a fourth microstrip line is provided on the back side. a slot line that is perpendicular to the connection position, one end of which is electromagnetically open at the connection part, and the other end of which is converted to the fourth microstrip line; and the second and third microstrip lines. A balanced mixer characterized in that two diodes are disposed on the surface of the substrate, one electrode of which is connected to a metal pattern, and the other electrode of which is connected to a metal pattern that is electromagnetically connected. (2) The distance from the branch point of the second and third microstrip lines to each diode is λN/4(
2. The balanced mixer according to claim 1, wherein N is a positive odd number.