HIGH FREQUENCY POWER DIVIDER

A high-frequency power divider includes an insulative substrate and a circuit on the substrate. The circuit includes an input end, first and second output ends, and a resistance element, First and second microstrip lines are between the input and first output ends. Other first and second microstrip lines are between the input and second output ends. The first microstrip lines are connected to the second microstrip lines, which are connected to the first or second output end. A third microstrip line is between one end of the resistance element and a connection point between the first and second microstrip lines. Another third microstrip line is between another end of the resistance element and a connection point between the other first and second microstrip lines. The high-frequency signal phase shift is 90 degrees for each of the first and second microstrip lines and 180 degrees for the third microstrip line.

TECHNICAL FIELD

Embodiments relate to a high-frequency power divider.

BACKGROUND ART

For example, Wilkinson power dividers are used for power distribution in high-frequency bands such as microwaves. When, however, a Wilkinson power divider is multistaged to increase the bandwidth, the power loss is increased, and the circuit scale becomes large.

PRIOR ART DOCUMENTS

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Embodiments provide a high-frequency power divider in which a wider bandwidth is possible.

Solution to Problem

A high-frequency power divider according to an embodiment includes an insulative substrate and a circuit located on the substrate. The circuit includes an input end, a first output end, a second output end, multiple first microstrip lines, multiple second microstrip lines, multiple third microstrip lines, and a resistance element. One first microstrip line among the multiple first microstrip lines and one second microstrip line among the multiple second microstrip lines are located between the input end and the first output end. Another first microstrip line among the multiple first microstrip lines and another second microstrip line among the multiple second microstrip lines are located between the input end and the second output end. The input end is connected to a first end of the one first microstrip line and a first end of the other first microstrip line. A second end of the one first microstrip line is connected to a first end of the one second microstrip line; and a second end of the one second microstrip line is connected to the first output end. A second end of the other first microstrip line is connected to a first end of the other second microstrip line; and a second end of the other second microstrip line is connected to the second output end. A first end of one third microstrip line among the multiple third microstrip lines is connected to the second end of the one first microstrip line and the first end of the one second microstrip line. A second end of the one third microstrip line is connected to one end of the resistance element. A first end of another third microstrip line among the multiple third microstrip lines is connected to the second end of the other first microstrip line and the first end of the other second microstrip line. A second end of the other third microstrip line is connected to another end of the resistance element. A phase shift of a high-frequency signal between the first end and the second end of each of the multiple first microstrip lines is 90 degrees; and a phase shift of a high-frequency signal between the first end and the second end of each of the multiple second microstrip lines is 90 degrees. A phase shift of a high-frequency signal between the first end and the second end of each of the multiple third microstrip lines is 180 degrees.

DESCRIPTION OF EMBODIMENTS

Embodiments will now be described with reference to the drawings. The same portions in the drawings are marked with the same numerals; a detailed description is omitted as appropriate; and different portions are described. The drawings are schematic or conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. Also, the dimensions and proportions may be illustrated differently among drawings, even when the same portion is illustrated.

Furthermore, the arrangements and configurations of the portions are described using an X-axis, a Y-axis, and a Z-axis shown in the drawings. The X-axis, the Y-axis, and the Z-axis are orthogonal to each other and respectively represent an X-direction, a Y-direction, and a Z-direction. Also, there are cases where the Z-direction is described as up, and the opposite direction is described as down.

FIG.1is a schematic plan view illustrating a high-frequency power divider1according to an embodiment. The high-frequency power divider1includes, for example, multiple microstrip lines and a resistance element Rb located on a surface of an insulating substrate RS. The insulating substrate RS includes, for example, a resin or a ceramic, and includes a not-illustrated metal layer on the back side. The multiple microstrip lines include, for example, copper (Cu) or gold (Au).

As shown inFIG.1, the high-frequency power divider1includes an input end Pin, a first output end Pout1, a second output end Pout2, multiple first microstrip lines10aand10b, multiple second microstrip lines20aand20b, multiple third microstrip lines30aand30b, and the resistance element Rb.

For example, the input end Pin, the first output end Pout1, and the second output end Pout2are arranged along the surface of the insulating substrate RS in a first direction, e.g., the Y-direction. The input end Pin is located between the first output end Pout1and the second output end Pout2. Also, for example, the input end Pin and the resistance element Rb are arranged along the surface of the insulating substrate in a second direction, e.g., the X-direction, which crosses the first direction.

The first microstrip line10aand the second microstrip line are located between the input end Pin and the first output end Pout1. Also, the first microstrip line10band the second microstrip line20bare located between the input end Pin and the second output end Pout2.

The first microstrip lines10aand10band the second microstrip lines20aand20beach extend in the Y-direction. Each of the first microstrip lines10aand10band the second microstrip lines20aand20bincludes one end (hereinbelow, a first end) and another end (hereinbelow, a second end) without branching.

The input end Pin is connected to the first end of the first microstrip line10aand the first end of the first microstrip line10b.

The second end of the first microstrip line10ais connected to the first end of the second microstrip line20a. The second end of the second microstrip line20ais connected to the first output end Pout1.

The second end of the first microstrip line10bis connected to the first end of the second microstrip line20b. The second end of the second microstrip line20bis connected to the second output end Pout2.

The third microstrip line30ais located between the resistance element Rb and a connection point CP1between the first microstrip line10aand the second microstrip line20a. A first end of the third microstrip line30ais connected to the second end of the first microstrip line10aand the first end of the second microstrip line20aat the connection point CP1. Also, a second end of the third microstrip line30ais connected to one end of the resistance element Rb.

The third microstrip line30bis located between the resistance element Rb and a connection point CP2between the first microstrip line10band the second microstrip line20b. A first end of the third microstrip line30bis connected to the second end of the first microstrip line10band the first end of the second microstrip line20bat the connection point CP2. Also, a second end of the third microstrip line30bis connected to another end of the resistance element Rb.

FIG.2is a circuit diagram illustrating the high-frequency power divider1according to the embodiment. As shown inFIG.2, the input end Pin, the first output end Pout1, and the second output end Pout2are provided so that each has a characteristic impedance Zport of 50Ω.

The first microstrip lines10aand10bare provided so that each has a characteristic impedance Z1and a phase shift of 90 degrees for the high-frequency signal between the first end and the second end.

The second microstrip lines20aand20bare provided so that each has a characteristic impedance Z2and a phase shift of degrees for the high-frequency signal between the first end and the second end.

The third microstrip lines30aand30bare provided so that each has a characteristic impedance Z3and a phase shift of 180 degrees for the high-frequency signal between the first end and the second end.

FIG.3is a graph illustrating a characteristic of the high-frequency power divider1according to the embodiment. The horizontal axis is the value of the signal frequency normalized by the center frequency. The vertical axis is the absolute value of S11(dB).FIG.3shows a characteristic SP1of the high-frequency power divider1according to the embodiment and a characteristic SP2of a high-frequency power divider2according to a comparative example (seeFIG.5).

FIG.5Ais a schematic plan view showing the high-frequency power divider2; andFIG.5Bis a circuit diagram showing the high-frequency power divider2. As shown in FIG. the high-frequency power divider2is located on a surface of the insulating substrate RS. The high-frequency power divider2is a Wilkinson power divider.

The high-frequency power divider2includes the input end Pin, the first output end Pout1, the second output end Pout2, the first microstrip line10a, the first microstrip line10b, and the resistance element Rb. For example, the input end Pin, the first output end Pout1, and the second output end Pout2are arranged in the X-direction; and the input end Pin and the resistance element Rb also are arranged in the X-direction.

The first microstrip line10ais located between the input end Pin and the first output end Pout1. The first end of the first microstrip line10ais connected to the input end Pin; and the second end of the first microstrip line10ais connected to the one end of the resistance element Rb.

The first microstrip line10bis located between the input end Pin and the second output end Pout2. The first end of the first microstrip line10bis connected to the input end Pin; and the second end of the first microstrip line10bis connected to the other end of the resistance element Rb.

The first output end Pout1and the second output end Pout2are connected respectively to the one end and the other end of the resistance element Rb.

As shown inFIG.5B, the input end Pin, the first output end Pout1, and the second output end Pout2are provided so that each has the characteristic impedance Zport of 50Ω. The first microstrip lines10aand10bare provided so that each has the characteristic impedance Z1and a phase shift of 90 degrees for the high-frequency signal between the first end and the second end.

As shown inFIG.3, the characteristic SP2of the high-frequency power divider2has a minimum value at the center frequency. The center frequency is, for example, 3 GHz. On the other hand, for example, for the characteristic SP1of the high-frequency power divider1, |S11| becomes small in the fractional bandwidth range of 0.67 to 1.33 corresponding to the bandwidth of 2 to 4 GHz. For example, looking at the bandwidth where |S11| is not more than −20 dB, the high-frequency power divider1has a wider fractional bandwidth than the high-frequency power divider2.

Also, as shown inFIG.1, the first and second output ends Pout1and Pout2of the high-frequency power divider1are arranged to be separated from each other in the Y-direction. It is therefore easier to connect to next-stage circuits compared to the high-frequency power divider2in which the first output end Pout1and the second output end Pout2are located at the two ends of the resistance element Rb.

FIG.4is a circuit diagram illustrating a high-frequency power divider3according to a modification of the embodiment. The high-frequency power divider3has a circuit configuration in which a power divider circuit having the same structure is connected in series to the first output end Pout1of the power distribution circuit shown inFIG.2.

As shown inFIG.4, the high-frequency power divider3further includes fourth microstrip lines40aand40b, fifth microstrip lines50aand50b, sixth microstrip lines60aand60b, and a resistance element Rb2.

The fourth microstrip line40aand the fifth microstrip line50aare located between the second microstrip line20aand the first output end Pout1. A first end of the fourth microstrip line40ais connected to the second end of the second microstrip line and a second end of the fourth microstrip line40ais connected to a first end of the fifth microstrip line50a. A second end of the fifth microstrip line50ais connected to the first output end Pout1.

The fourth microstrip line40band the fifth microstrip line are located between the second microstrip line20aand the second output end Pout2. A first end of the fourth microstrip line40bis connected to the second end of the second microstrip line20a; and a second end of the fourth microstrip line40bis connected to a first end of the fifth microstrip line50b. A second end of the fifth microstrip line50bis connected to the second output end Pout2.

The sixth microstrip line60ais located between the resistance element Rb2and a connection point CP3between the fourth microstrip line40aand the fifth microstrip line50a. A first end of the sixth microstrip line60ais connected to the second end of the fourth microstrip line40aand the first end of the fifth microstrip line50aat the connection point CP3. Also, a second end of the third microstrip line60ais connected to one end of the resistance element Rb2.

The sixth microstrip line60bis located between the resistance element Rb2and a connection point CP4between the fourth microstrip line10band the fifth microstrip line50b. A first end of the sixth microstrip line60bis connected to the second end of the fourth microstrip line40band the first end of the fifth microstrip line50bat the connection point CP4. Also, a second end of the sixth microstrip line60bis connected to another end of the resistance element Rb2.

The fourth microstrip lines40aand40bare provided so that each has a characteristic impedance Z4and a phase shift of degrees for the high-frequency signal between the first end and the second end.

The fifth microstrip lines50aand50bare provided so that each has a characteristic impedance Z5and a phase shift of 90 degrees for the high-frequency signal between the first end and the second end.

The sixth microstrip lines60aand60bare provided so that each has a characteristic impedance Z6and a phase shift of 180 degrees for the high-frequency signal between the first end and the second end.

The high-frequency power divider3further includes a circuit (not illustrated) similar toFIG.2connected to the second microstrip line20b. The high-frequency power divider3further includes a third output end Pout3and a fourth output end Pout4(not illustrated).

Although a configuration in which two stages of the circuit shown inFIG.2are connected is shown in the example, the embodiments are not limited thereto. For example, when N stages of the circuit shown inFIG.2are included, the number of output ends is 2N. In other words, a high-frequency power divider that has 2N output ends can be configured.

While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. These novel embodiments may be embodied in a variety of other forms; and various omissions, substitutions, and changes may be made without departing from the spirit of the inventions. Such embodiments and their modifications are within the scope and spirit of the inventions, and are within the scope of the inventions described in the claims and their equivalents.

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