Circuit board and communication device with side coupler

A communication device includes a circuit board having an upper surface and a lower surface, an upper housing disposed on the upper surface, and a lower housing disposed on the lower surface. The circuit board includes a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity. The upper housing includes a depression corresponding to the top cavity, and the lower housing includes an aperture corresponding to the bottom cavity.

TECHNICAL FIELD

The present disclosure relates to a circuit board and a communication device, and more particularly, to a circuit board and a communication device with a side coupler for detecting output power.

DISCUSSION OF THE BACKGROUND

In conventional communication devices, an extra power directional coupler or power-sensing integrated circuit (IC) is typically required in the amplifiers on the circuit board to monitor the power output of satellites or wireless signal point-to-point converters. However, installing power directional couplers or power-sensing ICs creates some drawbacks, such as the need for a larger board area when such devices are installed. Furthermore, the detection circuit generates additional insertion loss. In addition, it increases the overall cost of the circuit board.

SUMMARY

One aspect of the present disclosure provides a circuit board, comprising a substrate having an upper surface and a lower surface; a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity.

In some embodiments, the side coupler comprises a linear conductor having a first end extending into the bottom cavity and a second end connected to a through conductor, and the through conductor penetrates the substrate.

In some embodiments, the circuit board further comprises a power conversion circuit disposed on the upper surface and electrically connected to the through conductor of the side coupler.

In some embodiments, the circuit board further comprises a plurality of conductors electrically connecting the top metal frame to the bottom metal frame.

In some embodiments, the top metal frame comprises a top passage gap, and the microstrip line extends into the top cavity through the top passage gap.

In some embodiments, the bottom metal frame comprises a bottom passage gap, and the side coupler extends into the top cavity through the bottom passage gap.

In some embodiments, the bottom metal frame and the side coupler are disposed on the same plane.

In some embodiments, the side coupler is electrically isolated from the bottom metal frame.

Another aspect of the present disclosure provides a communication device, comprising a circuit board, an upper housing disposed on an upper side of the circuit board, and a lower housing disposed on a lower side of the circuit board. The circuit board comprises a substrate having an upper surface and a lower surface; a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity.

In some embodiments, the upper space has a height of one quarter of the operating wavelength of the communication device.

In some embodiments, the communication device further comprises an amplifier disposed on the upper surface and electrically connected to the microstrip line.

In some embodiments, the side coupler comprises a linear conductor having a first end extending into the bottom cavity and a second end connected to a through conductor, and the through conductor penetrates the substrate.

In some embodiments, the communication device further comprises a power conversion circuit disposed on the upper surface and electrically connected to the through conductor of the side coupler.

In some embodiments, the circuit board further comprises a plurality of conductors electrically connecting the top metal frame to the bottom metal frame.

In some embodiments, the top metal frame comprises a top passage gap, and the microstrip line extends into the top cavity through the top passage gap.

In some embodiments, the bottom metal frame comprises a bottom passage gap, and the side coupler extends into the top cavity through the bottom passage gap.

In some embodiments, the bottom metal frame and the side coupler are disposed on the same plane.

In some embodiments, the side coupler is electrically isolated from the bottom metal frame.

In some embodiments, the depression forms a reflection waveguide.

In some embodiments, the aperture forms an output waveguide.

In the present disclosure, the coupling loss of the side coupler can be changed by adjusting the length (L) of the side coupler, so as to control the coupling loss to fit the desired linear power detection range.

In the present disclosure, the side coupler is used to replace the conventional power directional coupler, and the microstrip line and the side coupler are coupled to generate the required power for further conversion of the power to the voltage. In this way, the size of the circuit board can be effectively reduced and the manufacturing cost of the expensive circuit board can be reduced correspondingly.

The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and technical advantages of the disclosure are described hereinafter and form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the concepts and specific embodiments disclosed may be utilized as a basis for modifying or designing other structures, or processes, for carrying out the purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit or scope of the disclosure as set forth in the appended claims.

DETAILED DESCRIPTION

FIG. 1is schematic diagram of a communication device100in accordance with some embodiments of the present disclosure. Referring toFIG. 1, in some embodiments, the communication device100, such as a microwave communication device, includes a substrate110, such as an FR-4 substrate. In some embodiments, the upper side and the lower side of the substrate110have an upper space120and a lower space130, respectively.

FIG. 2AandFIG. 2Bare schematic diagrams of the communication device100inFIG. 1in accordance with some embodiments of the present disclosure. In some embodiments, the substrate110of the communication device100includes an upper surface110A and a lower surface110B, and the upper space120and the lower space130are disposed respectively over the upper surface110A and below the lower surface110B. In some embodiments, the upper space120may be implemented by disposing a hollow shell over the upper surface110A of the substrate110. In some embodiments, the lower space130implements an output waveguide, which is a passage space for the microwave signals. In some embodiments, the upper space120implements a reflection waveguide, and the height of the upper space120is one-quarter of the designed operating wavelength of the communication device100, wherein the height is designed so that the microwave signals are reflected back to the lower space130.

Referring toFIG. 1,FIG. 2AandFIG. 2B, in some embodiments, the communication device100further includes a microstrip line11and a side coupler112disposed on different planes of the communication device100. In some embodiments, the microstrip line111and the side coupler112are disposed on different sides of the substrate110; for example, the microstrip line111is disposed on the upper surface110A, while the side coupler112is disposed on the lower surface110B.

Referring toFIG. 1andFIG. 2A, in some embodiments, the microstrip line111serves as an input terminal connected to an electronic device such a signal amplifier10, and the signals from the signal amplifier10are converted by a microstrip-to-waveguide conversion mechanism implemented on the upper surface110A and in the upper space120. In some embodiments, in the lower space130, the converted signal is then conducted to the side coupler112on the lower surface110B.

Referring toFIG. 1andFIG. 2B, in some embodiments, a major portion of the microwave power from the microstrip line111is outputted through the output waveguide (the lower space130) to the outside of the communication device100, while a minor portion of the microwave power from the microstrip line111can be coupled out of the output waveguide (the lower space130) by the side coupler112in the lower space130. In some embodiments, the coupling loss of the side coupler112can be adjusted by changing the length (L) of the side coupler112, and the length (L) can be adjusted in view of the power requirement of the communication device100. In some embodiments, the minor portion of the microwave power coupled out by the side coupler112is then passed to a power conversion circuit11on the upper surface110A for further conversion to a voltage signal.

Referring toFIG. 1andFIG. 2A, in some embodiments, the power conversion circuit11is disposed on the upper surface110A of the substrate110and connected to the side coupler112. In some embodiments, a through conductor113penetrates the substrate110from the lower surface110B to the upper surface110A, and the through conductor112A electrically connects the side coupler112on the lower surface110B to the power conversion circuit11on the upper surface110A.

Some coupling losses are generated during the coupling process. In some embodiments, in order to make the power detection range of the communication equipment fall within a preferable linear region, i.e., a region where power and voltage conversion are relatively linear; the coupling loss can be changed by adjusting the coupling ratio of the side coupler112, e.g., by changing the length (L) of the side coupler112to control the coupling loss to fit the desired linear power detection range.

FIG. 3AandFIG. 3Bare schematic diagrams of a circuit board20at different viewing angles in accordance with some embodiments of the present disclosure. In some embodiments, the circuit board20comprises a substrate21, such as an FR-4 substrate, having an upper surface21A and a lower surface21B; a top metal frame23disposed on the upper surface21A, wherein the top metal frame23defines a top cavity23A; a bottom metal frame25disposed on the bottom surface21B, wherein the bottom metal frame25defines a bottom cavity25A corresponding to the top cavity23A; a microstrip line27disposed on the upper surface21A and extending into the top cavity23A; and a side coupler29disposed on the lower surface21B and extending into the bottom cavity25A. In some embodiments, the circuit board20further comprises a plurality of conductors33such as conductive through vias/holes electrically connecting the top metal frame23to the bottom metal frame25.

Referring toFIG. 3B, in some embodiments, the side coupler29comprises a linear conductor30having a first end30A in the bottom cavity25A and a second end30B connected to a through conductor31, and the through conductor31penetrates the substrate21. In some embodiments, the bottom metal frame25also defines a bottom passage gap29A, and the side coupler29extends into the bottom cavity25A through the bottom passage gap29A, and the side coupler29is electrically isolated from the bottom metal frame25. In some embodiments, the bottom metal frame25and the side coupler29are disposed on the same plane, and can be integrally formed by the same fabrication process.

Referring toFIG. 3A, in some embodiments, the circuit board20comprises a power conversion circuit35such as a power-to-voltage converter disposed on the upper surface21A and electrically connected to the through conductor31, which further connects to the side coupler29on the lower surface21B. In some embodiments, the top metal frame23also defines a top passage gap27A, the microstrip line27extends into the top cavity23A through the top passage gap27A, and the microstrip line27is electrically isolated from the top metal frame23.

FIG. 4AandFIG. 4Bare schematic assembled diagrams of a communication device200at different viewing angles in accordance with some embodiments of the present disclosure, andFIG. 4CandFIG. 4Dare schematic disassembled diagrams of the communication device200at different viewing angles in accordance with some embodiments of the present disclosure. In some embodiments, the communication device200comprises the circuit board20inFIG. 3A, an upper housing220disposed on the upper surface21A of the circuit board20, and a lower housing230disposed on the lower surface21B of the circuit board20.

Referring toFIG. 4AandFIG. 4C, in some embodiments, the power conversion circuit35is disposed on the upper surface21A of the circuit board20and is connected to the side coupler29on the lower surface21B via the through conductor31penetrating the circuit board20. In some embodiments, the power conversion circuit35is not covered by the upper housing220. In some embodiments, the upper housing220comprises a depression221corresponding to the top cavity23A, and the depression221implements the upper space120inFIG. 1, serving as the reflection waveguide.

Referring toFIG. 4BandFIG. 4D, in some embodiments, the lower housing230comprises an aperture231corresponding to the bottom cavity25A. In some embodiments, the aperture231of the lower housing230implements the lower space130inFIG. 1, serving as an output waveguide, which is a passage space for the microwave signals.

FIG. 5is a graph showing the insertion loss of the communication device200and a comparative communication device at different frequencies in accordance with some embodiments of the present disclosure, andFIG. 6is a graph showing the return loss of the communication device200and the comparative communication device at different frequencies in accordance with some embodiments of the present disclosure.

Referring toFIG. 5, the curve510A represents the insertion losses of the comparative communication device without the side coupler29, and the curve520A represents the insertion losses of the communication device200with the side coupler29. The range R indicates the designed operating frequency range of 14.0-14.5 GHz. As can be seen fromFIG. 5, the difference in terms of the insertion loss between the curve510A (without the side coupler) and the curve520A (with the side coupler) is only about 0.01 dB. In other words, incorporating the side coupler29in the communication device200incurs a negligible insertion loss. In contrast, conventionally incorporating the power directional couplers or the power detection ICs can generate an insertion loss of 0.4 to 0.6 dB.

Referring toFIG. 6, the curve510B represents the return losses of the comparative communication device without the side coupler29, and the curve520B represents the return losses of the communication device200with the side coupler29. It can be seen fromFIG. 6that there is no significant difference between the curve510B and the curve520B. In other words, incorporating the side coupler29into the communication device200does not cause significant return loss.

FIG. 7is a graph showing the coupling loss of the communication device200inFIG. 4Aat different frequencies in accordance with some embodiments of the present disclosure, andFIG. 8is a graph showing the transfer waveforms of the power conversion circuit35such as a Schottky diode at different frequencies in accordance with some embodiments of the present disclosure. In the present disclosure, the coupling loss of the side coupler29can be changed by adjusting the length (L) of the side coupler29, so as to control the coupling loss to fit the desired linear power detection range of the power conversion circuit35.

Referring toFIG. 7, in an embodiment, when the power requirement of the communication device200is set to be 30 dBm, the coupling loss is about −28 dB in the designed operating frequency range of 14.0-14.5 GHz; referring toFIG. 8, the transfer waveforms of the power conversion circuit35have a linear region between −3.0 dBm and 5.0 dBm at input (horizontal axis). In other words, the difference between the power requirement (30 dBm) and the coupling loss (−28 dB) is about 2 dB, which falls within the linear region of the power conversion circuit35. In case of different power requirements of the communication device200, the length (L) of the side coupler112can be changed so that the difference between the power requirement and the coupling loss falls within the linear region of the power conversion circuit35.

In the present disclosure, the side coupler29is used to replace the conventional power directional coupler, and the microstrip line27and the side coupler29are coupled to generate the required power for further conversion of the coupled power to the voltage. In this way, the size of the circuit board can be effectively reduced and the manufacturing cost of the expensive circuit board can be reduced correspondingly.

One aspect of the present disclosure provides a circuit board. The circuit board comprises a substrate having an upper surface and a lower surface; a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity.

Another aspect of the present disclosure provides a communication device. The communication device comprises a circuit board, an upper housing disposed on an upper side of the circuit board, and a lower housing disposed on a lower side of the circuit board. The circuit board comprises a substrate having an upper surface and a lower surface; a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity.