TWI636619B - Coaxcial cable power divider - Google Patents

Abstract

A coaxial cable power distribution combining device comprises first, second and third coaxial cables and a section of microstrip circuit. The microstrip is an impedance matching converter. The central conductors of the first and second coaxial cables are electrically connected to the upper layer of one end of the microstrip, and the outer conductor is electrically connected to the grounding surface of the microstrip at the same end; the central conductor of the third coaxial cable is electrically connected to the upper layer of the other end of the microstrip, and the outer layer thereof The conductor is electrically connected to the grounding surface of the other end of the microstrip. If the signal energy is fed by the third coaxial wire, the energy is distributed to the first and second coaxial cables via the microstrip circuit, and the structure is a power splitter; if the signal energy is entered by the first and second coaxial cables, then The strap is integrated into the third coaxial cable and the structure is a power combiner.

Description

Coaxial cable power distribution combined device

The present invention relates to a power splitter; and more particularly to an electromagnetic wave power splitter for use in a structure in which a coaxial cable transmits electromagnetic waves.

A conventional electromagnetic wave power splitter is a combination of three coaxial cables. The interconnection mode is that the three center wires are directly connected, and the outer conductors of the coaxial cable are also connected to each other in a T or Y-shaped structure. The direct connection structure can be regarded as two coaxial cables connected in parallel and then connected in series with the third coaxial cable. For the same three coaxial cables, such a connection does not match its electrical impedance, which will cause energy reflection during power transmission and reduce energy transmission efficiency. The improvement of the transmission structure usually adds or designs another coaxial cable with different characteristic impedances in front of the third coaxial cable in series as impedance matching, but the design and manufacturing cost are high due to the three-dimensional structure.

Another conventional electromagnetic wave power splitter is a combination of three microstrip lines in a printed circuit. Usually a microstrip is added as an impedance converter to satisfy the impedance matching. The length of the added microstrip is a quarter guided wave. long. The fabrication of printed circuits is easier than coaxial cables, but for energy transmission losses, the microstrips in printed circuits have greater transmission losses than coaxial cables. The high-frequency circuit above the X-band has a severe microstrip line loss and is generally not applicable to transmission designs above one wavelength.

In view of the above problems, it is an object of the present invention to provide an electromagnetic wave distributing apparatus which is easy to manufacture and which is applicable to a low loss energy transmission architecture.

The invention relates to a coaxial cable power distribution device, comprising first, second and third coaxial cables and a section of microstrip circuit. The microstrip circuit includes an upper metal microstrip, a circuit substrate and a lower metal ground plane; the upper microstrip length is transmitted as a wavelength matching electromagnetic wave wavelength as an impedance matching converter. The center conductors of the first and second coaxial cables are electrically connected to the upper layer of one end of the microstrip, and the outer conductors of the first and second coaxial cables are electrically connected to the grounding surface of the microstrip. The center wire of the third coaxial cable is electrically connected to the upper layer of the other end of the microstrip, and the outer conductor of the third coaxial cable is electrically connected to the grounding surface of the other end of the microstrip.

Because the coaxial cable and the microstrip line are two different electromagnetic wave conducting structures, whether the electrical connection between the central conductor of the coaxial cable and the upper layer of the microstrip or the electrical connection between the outer conductor of the coaxial cable and the ground plane of the microstrip must be considered. Discontinuity of transmission. The invention selects that the thickness of the printed circuit board is close to the radius of the coaxial cable, and the central axis of the coaxial cable can be horizontally placed on the upper microstrip for soldering; and the circuit substrate is partially grooved so that the coaxial cable can be embedded in the circuit In the trench of the substrate, the embedded depth is about the radius of the coaxial cable, which facilitates the connection of the outer conductor of the coaxial cable to the microstrip line ground plane. This design can reduce the discontinuity of electromagnetic waves in different transmission structures, reduce energy scattering loss, and improve impedance matching.

The above-mentioned coaxial cable outer conductor and the microstrip grounding surface are electrically connected, and in addition to being directly contactable, a circuit metal solder joint may be designed on both sides of the groove of the circuit substrate to weld the solder joint and the outer conductor of the coaxial cable. . Thus, the electric field distribution of the discontinuous surface of the electromagnetic transmission can be adjusted, and the coaxial coaxial cable can be fixed on the circuit substrate.

In addition, the conductive hole of the circuit can be added between the metal solder joint and the ground plane of the circuit board to adjust the current of the discontinuous surface of the electromagnetic transmission, and the impedance matching is corrected.

If the signal energy is fed by the third coaxial wire, the energy is distributed to the first and second coaxial cables via the microstrip circuit, and the structure is a power splitter; if the signal energy is entered by the first and second coaxial cables, then The strap is integrated into the third coaxial cable and the structure is a power combiner.

Compared with the prior art microstrip power splitter, the present invention uses a coaxial cable as an electromagnetic wave energy transmission structure, which can be used for applications with lower energy loss. Compared with the conventional coaxial cable power splitter, the present invention adopts a microstrip impedance matching converter, so that it is easy to design and manufacture; the power splitter designed in combination with the two advantages can be applied to a planar circuit design, such as a planar array antenna; Can also be applied to coaxial cable transmission systems, such as cable distributors, etc., to increase applications Diversity.

1‧‧‧First coaxial cable

2‧‧‧Second coaxial cable

3‧‧‧ Third coaxial cable

11, 21, 31‧‧‧ center shaft wire

12, 22, 32‧‧‧ outer conductor

13, 23, 33‧‧‧ insulators

4‧‧‧Microstrip line

41‧‧‧Upper microstrip

42‧‧‧Circuit surface of circuit board

43‧‧‧Circuit substrate trench

44‧‧‧ circuit board

51, 61, 71‧‧‧metal solder joints

52, 62, 72‧‧‧ circuit conductive through holes

Figure 1 is a schematic perspective view of the present invention.

Figure 2 is a graph showing the measured reflection coefficient and transmission coefficient of an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, reference is made to the first embodiment of the drawing, in which the components of the present invention are described with reference to the coaxial cable power distribution device of the present invention. The device comprises a first coaxial cable 1, a second coaxial cable 2, a third coaxial cable 3 and a section of microstrip circuit 4. The coaxial cables 1, 2, 3 each comprise a metal central axis conductor 11, 21, 31, a coaxial cylindrical outer conductor 12, 22, 32 coaxial with the central conductor, and an insulator 13 intermediate the central conductor and the outer conductor. , 23, 33. The microstrip circuit 4 includes an upper metal microstrip 41, a circuit substrate 44, and a lower metal ground plane 42. The length of the upper microstrip 41 is based on the principle that the wavelength of the electromagnetic wave is transmitted by a quarter. The impedance of the coaxial cable in parallel with the previous stage and the impedance of the rear-stage coaxial cable are calculated by the design principle of the impedance matching converter, and the width of the upper microstrip 41 can be obtained. The first and second coaxial cable center wires 11, 21 are electrically connected to the upper layer of one end of the microstrip 41, and the outer conductors 12, 22 are electrically connected to the grounding surface 42 of the microstrip 41 at the same end. The third coaxial cable center wire 31 is electrically connected to the upper end of the other end of the microstrip 41, and the outer conductor 32 is electrically connected to the other end ground plane 42 of the microstrip 41.

The coaxial cable central axes 11, 21, 31 are placed on the upper microstrip 41 for soldering; and the circuit substrate is grooved 43 so that the coaxial cable can be embedded in the circuit substrate trench to facilitate the coaxial cable outer conductor and the microstrip line ground plane. connection.

The circuit metal pads 51, 61, 71 are designed on the upper side of the coaxial cable trenches on the circuit substrate, and the solder joints and the outer conductors 12, 22, 32 of the coaxial cable are soldered respectively.

The circuit conductive vias 52, 62, 72 are respectively connected to the metal pads 51, 61, 71 and the ground plane 42 of the circuit substrate to ensure the grounding characteristics of the outer conductors 12, 22, 32 of the coaxial cable.

Figure 2 is a diagram showing the measured reflection coefficient and transmission coefficient of the embodiment of the present invention. The embodiment uses a ceramic circuit substrate having a dielectric constant of 3.33 and a thickness of 0.51 mm. A copper outer conductor, a coaxial cable having a diameter of 1.2 mm and a length of 85 mm is used. The measured third coaxial cable reflection coefficient S11 is -13.17 dB at 10.9 GHz. If there is no impedance matcher, the theoretical reflection coefficient will be greater than -10dB. The measured third to first coaxial cable transmission coefficient S21 is -3.57 dB, and the theoretical completely lossless power splitter is -3 dB. The measurement results of this embodiment show that the present invention is applicable to a higher loss circuit designed and manufactured in the X-band.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

Claims (4)

A coaxial cable power distribution combining device comprising: a triaxial cable each comprising a metal central axis wire, a hollow cylindrical metal conductor coaxial with the center wire, and an insulator interposed between the center wire and the outer conductor; and a microstrip circuit comprising a metal upper microstrip, a circuit insulating substrate and a metal lower ground plane; wherein the first and second coaxial cable center wires are micro-charged to the upper layer of the microstrip circuit, and the first and second coaxial cable outer conductors The grounding surface of the lower end of the microstrip circuit is electrically connected, the central conductor of the third coaxial cable is micro-charged to the upper end of the microstrip circuit, and the outer conductor of the third coaxial cable is electrically connected to the lower ground plane of the other end of the microstrip circuit; The energy signal is fed by the third coaxial cable and distributed to the first and second coaxial cables or fed by the first and second coaxial cables to the third coaxial cable. The coaxial cable power distribution combining device according to claim 1, wherein the microstrip circuit has a microstrip length in which the length of the microstrip transmits the wavelength of the electromagnetic wave. The coaxial cable power distribution combining device according to claim 1, wherein the circuit board of the microstrip circuit has a groove so that the coaxial cable can be embedded in the circuit substrate. The coaxial cable power distribution combining device according to claim 1, further comprising: a metal solder joint located on a circuit substrate below and on both sides of the coaxial cable, soldering the solder joint and the coaxial cable Outer conductor; circuit conductive through hole, the conductive through hole of the circuit is connected to the metal solder joint and the circuit base The ground plane of the board.