KR20030091522A - A microwave directional coupler - Google Patents

Abstract

PURPOSE: A microwave directional coupler is provided to widen the width of micro strips for connecting and simplify a fabricating process by using the micro strips for connecting and the micro strips for non-connecting. CONSTITUTION: A microwave directional coupler includes a first to a fourth input/output terminals(301-304), a first to a fourth micro strips(305-308) for connecting, and a fifth and a sixth micro strips(309,310) for non-connecting. The first to the fourth input/output terminals(301-304) are formed at a left side and a right side of the microwave directional coupler. The first to the fourth micro strips(305-308) are formed in parallel to the first to the fourth input/output terminals(301-304). The fifth and the sixth micro strips(309,310) are used for connecting the micro strips between termination portions of two micro strips of the first to the fourth micro strips(305-308). The termination portions are connected by a wire bonding method.

Description

Microwave directional coupler

The present invention relates to a frequency mixer used for frequency conversion in a wireless communication device and an electronic device, or a directional coupler used in a signal detector, a power amplifier, an antenna feed line, and the like for detecting a state of a signal.

In general, in the circuits that process radio frequency (RF) and microwave signals such as mixers, power amplifiers, and phase shifters, the operation of power distribution is a directional coupler. It can be performed by (Directional Coupler). In general, a directional coupler is constructed by using electromagnetic coupling that occurs when a transmission line through which an electrical signal can be transmitted is placed close to each other. The magnitude of the signal induced on the line combined with the signal applied line is determined by the structure of the combiner. In the case of simply detecting the signal size of the line to which the signal is applied, the directional coupler uses a directional coupler having a structure in which the coupling amount may be small. However, if the power needs to be equally distributed, such as a balanced mixer or power amplifier, use a directional coupler with a large coupling.

FIG. 1 shows the configuration of a quarter-wavelength distributed coupling type coupler as a structure of the most typical directional coupler used in a printed circuit board. The dotted pattern is an electric signal transmission line formed by etching or electrode printing. When the signal is applied to one of the input / output terminals 101, 102, 103, 104 and the other terminals are impedance matched, the signal is induced to the relative line through the coupling lines 105 and 106, and the coupling degree is determined by the spacing of the coupling lines. Is determined. In order to achieve a high degree of coupling using a directional coupler, the spacing of the coupling lines must be made very small. There are many restrictions in designing this coupler. For example, in order to use a substrate with a dielectric constant of 2.2, a substrate of 0.5 mil (mil 1/1000 inch) must be used, which is very unrealistic. Therefore, it is difficult to fabricate and is mainly used when a low degree of bonding is required.

FIG. 2 is a range type coupler designed to obtain a high coupling degree by changing the structure of FIG. 1. This coupler was proposed by Julius Lange, 1969 International Microwave Symposium, Dallas, Texas, May 5-7, IEEE Cat. NO. 69 C 6, pp. As disclosed in 10-13. The coupling lines 201, 202, 203, 204, and 205 are branched to generate more coupling, and wire bonding 206 is processed to connect each coupling line.

This coupler provides very good properties, but has the disadvantage that the material of the substrate to implement it is very expensive and the equipment for producing this coupler becomes very complicated. For example, when using a substrate of a material having a high dielectric constant, such as alumina, the gap width between the lines should be in the range of 20 to 55 micrometers. It must be designed.

Compared to the directional coupler of FIG. 1, the conventional directional coupler shown in FIG. 2 can obtain a high degree of coupling. Although the spacing of the coupling lines is somewhat wider, the line width is narrower and the structure is complicated. In particular, the manufacturing process is difficult because the wire bonding work for connecting each coupling line is involved.

It is an object of the present invention to provide a directional coupler having a high degree of bonding and having a wide width and spacing of a coupling line.

Another object of the present invention is to provide a directional coupler having a structure that can maintain a high degree of coupling even by increasing the distance between the coupling lines by using a double bond phenomenon.

It is still another object of the present invention to provide a directional coupler having a structure that can replace the wire bonding portion with a surface mount chip.

Still another object of the present invention is to provide a directional coupler having a structure that can be easily manufactured by increasing the spacing between the coupling lines to improve productivity.

A directional coupler according to the present invention for achieving the above object is a microwave directional coupler for forming a coupling line on a single dielectric board, four input and output terminals formed in pairs on the left and right; Four micro strips for connecting parallel to and extending from the input and output terminals; The non-coupling line for connecting the coupling line between the two ends of the coupling line of the coupling line is characterized in that the configuration is added.

1 is a basic structural diagram of a conventional directional coupler,

2 is a structural diagram of a conventional directional coupler having a large coupling degree;

3 is an exemplary view of a directional coupler according to an embodiment of the present invention,

4 is an exemplary view of a directional coupler according to another embodiment of the present invention;

5 and 6 is an exemplary view configured so that the structure of the coupling line is symmetrical,

7 and 8 is an exemplary view of changing the non-coupling line portion of the directional coupler,

9 is a graph of scattering coefficient frequency characteristics of simulation results.

Hereinafter, with reference to the accompanying drawings will be described the configuration and the operation of the directional coupler according to the present invention.

Figure 3 is a directional coupler of the structure improved to the advantage of the width and spacing of the coupling line while using the wire bonding method of the conventional directional coupler having a large bonding degree as it is. In FIG. 3, the dotted pattern is a transmission line of an electric signal, and the directional coupler is an input / output terminal 301, 302, 303, 304, a coupling line 305, 306, 307, 308, or a non-coupling line 309 connecting each coupling line. , 310), and wire bonding.

Referring to the principle of operation, when a signal is applied through the terminal 301, electromagnetic coupling phenomenon occurs primarily through the coupling lines 305 and 306, and the combined signal with the incident signal is uncoupled lines 309 and 310, respectively. After progressing, the coupling phenomenon occurs once again in the coupling lines 307 and 308. As a result of the double coupling phenomenon as described above, even when the distance between the coupling lines is wide, a high degree of coupling can be obtained, thereby facilitating manufacturing. The length of the coupling line is one quarter wavelength of the frequency used, and the width and spacing can be easily calculated from the coupling line theory according to the desired coupling degree.

To illustrate the advantages of the present invention, when manufactured using a microstrip substrate having a characteristic impedance of 50 Hz, a thickness of 0.8 mm and a relative dielectric constant of 4.8 to have a 3 dB coupling degree at a center frequency of 2.14 Hz, the conventional directional coupler coupling line of FIG. The width of the furnace is 0.13 mm while the width of the bond line of the directional coupler structure of the present invention is 1.0 mm.

The directional coupler of FIG. 3 is about 7.7 times wider than the conventional directional coupler, making it easy to manufacture and connecting the coupling lines 305, 306, 307, and 308 as shown in FIG. 4 instead of wire bonding. There is an advantage that the wire bonding portion can be replaced with the surface mount chip 401.

5 and 6 are structural diagrams when the position of the coupling line is configured to have a symmetrical structure. FIG. 5 is configured in the form of a micro strip bent a plurality of times between the ends of two coupling lines in which a non-coupling line is connected to the inner side, and a surface-mount chip is formed between the ends of other coupling lines. Is formed. 6 is a shape of the non-coupling line is made of a line bent many times the same as in Figure 5, but the shape of the other coupling line is different. That is, an uncoupling line having a line width wider than the line width of the coupling line is formed at the end of the other coupling line to form a "U" shape.

7 and 8 are structural diagrams in the case where the non-coupling line portion is changed to a line having a structure that electrically plays the same role. In FIG. 7, a straight line having a line width thinner than the line width of the joining line between the end portions of two joining lines connected to the inner side of the joining line and a non-coupling line having a fan shape symmetric about the middle part of the straight line. Is formed, and the surface-mounted chip is formed between the ends of the remaining coupling lines.

8 is similar to that of FIG. 7 except that the non-coupling line portion formed at the end of the coupling line is connected to each other end and the output terminal by a surface mount chip, and the end of the other coupling line is wider than the line width of the coupling line. It is unusual that a non-coupling line having a line width is formed to form a "U" shape.

9 is a graph of scattering frequency characteristics obtained by simulating the structure of the present invention. As can be seen from the graph, it can be seen that there is a coupling degree of 3 dB in the center frequency band 2.14 ㎓.

As described above, the present invention forms the coupling line and the non-coupling line in the directional coupler using the electromagnetic coupling phenomenon of the transmission line formed on a single surface, so that the coupling phenomenon occurs in a double manner. It is effective to make it wider than the structure to facilitate the production. In addition, by extending the spacing between the coupling lines, the wire bonding part can be changed by the surface mounting method, thereby reducing manufacturing cost and time and increasing the reliability of the product.

Claims (8)

In a microwave directional coupler for forming a coupling line on a single dielectric board, Four input / output terminals formed in pairs on the left and right sides; Four micro strips for connecting parallel to and extending from the input and output terminals; A non-coupling line for connecting a coupling line is added between the ends of two coupling lines among the coupling lines, and a signal combined with a signal input through an input terminal passes through the non-coupling line to generate multiple coupling. Microwave directional coupler, characterized in that to induce. 2. The microwave directional coupler of claim 1, wherein the non-coupling line and the end of the coupling line are connected by wire bonding. 2. The microwave directional coupler of claim 1, wherein the non-coupling line and the end of the coupling line are connected by a surface mount chip. The chip of claim 1, wherein the non-coupling line is formed in the form of a micro strip bent a plurality of times between ends of two coupling lines connected to the inside thereof, and the surface-mount chip is disposed between the ends of the other coupling lines. Microchip directional coupler, characterized in that formed (chip). The method of claim 1; A straight line having a line width thinner than the line width of the joining line between the end portions of the two joining lines connected to the inside and a non-coupling line of symmetrical fan shape centered on the middle part of the straight line, the remaining joining line Microwave directional coupler, characterized in that the surface-mount chip is formed between the ends of the. In a microwave directional coupler for forming a coupling line on a single dielectric board, Four input / output terminals formed in pairs on the left and right sides; Four micro strips for connecting in parallel and staggered with each other; A non-coupling line is formed between the ends of two coupling lines connected to the inside of the coupling line, and each other end and the output terminal are connected by a surface-mount chip, and the ends of the other coupling lines are wider than the width of the coupling line. Microwave directional coupler, characterized in that the non-binding line having a line width is formed to form a "U" shape. 7. The microwave directional coupler of claim 6, wherein the non-coupling line is configured in the form of a micro strip bent many times. The non-coupling line is a straight line having a line width thinner than the line width of the coupling line between the end portions of two coupling lines connected to the inside and a fan shape symmetric about the middle portion of the straight line. Microwave directional coupler, characterized in that formed as.