Coupling device with electro-magnetic compensation

A coupling device with electro-magnetic compensation is provided. The coupling device includes a first substrate having a first signal line on a top surface of the first substrate and a second substrate having a second signal line on a top surface of the second substrate connected together with a bottom surface of the first substrate wherein the second signal line couples with the first signal line by a plurality of electrical-conductive through holes. One side of the first signal line lies a capacitor device parallel connected to a ground and the capacitor device plays the role of adjusting the amount of return loss, isolation capacity, and coupling effect so as to have transmitting speeds in first and second signal lines remain substantially the same and superior high frequency characteristics.

BACKGROUND OF THE INVENTION

Background

1. Field of the Invention

The present invention relates to a coupling device, and more particularly, to a coupling device with electro-magnetic compensation with the use of a parallel-connected capacitor device to the ground for adjusting the amount of return loss and isolation and getting the amount of coupling effect and output to a level as expected in order to obtain a better high frequency characteristic.

2. Description of the Prior Art

Please refer toFIG. 10where a prior art broadside coupler5includes an upper layer signal line51and a lower layer signal line52attached to substrates53and54, respectively. The upper signal line51couples with the lower signal line52by a plurality of electrical conductive through holes55. A medium layer (substrate)53is between the upper layer signal line51and the lower layer signal line52. The prior art coupling device5further includes an input end56, a coupling end57, an output end58, and an isolation end59.FIG. 8Ashows the result after having above mentioned ends measured and is indicative of inferior amount of return loss and isolation capacity with the amount of coupling effect and outputting not reaching to a level as anticipated.

The amount of coupling effect, return loss, and isolation capacity depend on the line width of the upper layer signal line51and the lower layer signal line52and the thickness of the medium layer between the upper layer signal line51and the lower layer signal line52. For the sake of obtaining better return loss and isolation capacity, the change to the line width of the upper layer signal line51and the lower layer signal line52or the thickness of the medium layer between the upper layer signal line51and the lower layer signal line52is inevitable, which is not preferred here.

Furthermore, the coupling device5couples the signal of the upper layer signal line51with that of its lower layer counterpart52through the medium layer between51and52and as the result odd/even mode problems would arise and the transmitting speeds of signals in the upper layer signal line51and the lower layer signal line52are different, leading to the inferior high frequency characteristic.

SUMMARY OF THE INVENTION

It is therefore a primary objective of the present invention to provide a coupling device with electro-magnetic compensation. With the use of a parallel-connected capacitor device, the present coupling device adjusts the amount of return loss and isolation capacity and makes the amount of coupling and output to reach to a level as anticipated. Furthermore, the present coupling device renders the consistency of signal transmitting speeds in two signal lines possible, achieving the goal of better high frequency characteristics.

In accordance with the claimed invention, a coupling device with electro-magnetic compensation includes a first substrate having a first signal line on a top surface of the first substrate, and a second substrate having a second signal line on a top surface of the second substrate connected together with a bottom surface of the first substrate wherein the second signal line is coupled with the first signal line by a plurality of electrical-conductive through holes, and one side of the first signal line lies a capacitor device parallel connected to a ground. The parallel-connected capacitor device could be either an open stub, a plurality of open stubs connected with others through wire bonding or ribbon bonding, or in the form of getting at least one capacitor connected to a grounded open stub.

It is an advantage of the present invention that with the setting of a parallel-connected capacitor device on one side or both sides of the signal line the present coupling device could have a superior isolation capacity and cut down the return loss while staying the coupling effect and amount of output at a level as expected and rendering the consistency of transmitting speeds in two signal lines possible in order to obtain a better high frequency characteristic.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer toFIG. 1of a schematic diagram showing a coupling device1according to the present invention. The coupling device1includes a first substrate11having a first signal line111thereon, a second substrate12having a second signal121thereon, and a parallel-connected capacitor device13. The first signal line111is on the top surface of the first substrate11and the bottom surface of the first substrate11attaches to the top surface of the second substrate12where lies the second signal line121. The second signal line121couples with the first signal line111by a plurality of through holes122and the parallel-connected capacitor device13is placed beside the first signal line111. The bottom surface of the second substrate12further connects to a multi-layer substrate14where other layout could be placed. The parallel-connected capacitor device13could be either an open stub, in the form of a plurality of open stubs connected with others by wire bonding or ribbon bonding, or a grounded capacitor device.

The first signal line111has four ends including an input end15, a coupling end16, an output end17, and an isolation end18. The coupling device according to the present invention1could get the amount of coupling effect, return loss, and the isolation capacity by measuring aforementioned four ends of the first signal line111. The amount of the coupling effect, return loss, and isolation capacity depend on the length width of first and second signal lines111and121, the thickness of medium layer between those two signal lines111and121(i.e., the thickness of the first substrate11), and the parallel-connected capacitor device13and the area thereof.

Please refer toFIG. 2of a structure schematic diagram of the first preferred embodiment according to the present invention. A coupling device1aincludes a first substrate11ahaving a first signal line111a, a second substrate12a(refer toFIG. 1) connected to the first substrate11aand having a second signal line121a(refer toFIG. 1also), and a parallel-connected capacitor device13abeside the first signal line111a. The current preferred embodiment employs an open stub131aas the parallel-connected capacitor device13aand the area of the open stub affects the amount of the coupling effect, return loss, and the isolation capacity of the coupling device1a. However, the use of an open stub as the parallel-connected capacitor device makes the change to the area of the open stub inconvenient where another new open stub must be replaced in order to make changes to the area of the open stub, leading to some inconvenience.

Please refer toFIG. 3of a top view of the second preferred embodiment according to the present invention. A coupling device1bincludes a first substrate11bhaving a first signal line111b, a second substrate attached to the first substrate and having a second signal line (refer toFIG. 1), and a parallel-connected capacitor device to the ground13bbeside the first signal line111b. In the current embodiment, the parallel-connected capacitor device to the ground13bis in the form of a plurality of open stubs131binterconnected with others through wire bonding or ribbon bonding, making the area of the parallel-connected capacitor device to the ground13badjustable without changing the entire open stub.

Please refer toFIG. 4of a top view of a third preferred embodiment according to the present invention. A coupling device1cincludes a first substrate11chaving a first signal line111c, a second substrate attached to the first substrate and having a second signal line (refer toFIG. 1), and a parallel-connected capacitor device to the ground13cbeside the first signal line111c. The parallel-connected capacitor device to the ground13cin the this preferred embodiment is in the form of having at least one capacitor133cwith one end attached to one side of the first signal line111cand the other end connected to a grounded open stub134c. The grounded open stub134chas at least one through hole1341cfor the purpose of grounding. The coupling device1cadjusts the value of the capacitor133cso as to control the amount of the coupling effect, return loss, and isolation capacity of the coupling device1citself.

Please refer toFIG. 5of another schematic diagram of a coupling device according to the present invention. A coupling device2includes a first substrate21having a first signal line211, a second substrate22having a second signal line221, a first parallel-connected capacitor device23, and a second parallel-connected capacitor device24. The bottom surface of the first substrate21connects to the top surface of the second substrate22. The second signal line221couples with the first signal line by a plurality of through holes222. The first parallel-connected capacitor device23and the second parallel-connected capacitor device24serving as the counterpart of the first parallel-connected capacitor device23in terms of the placement lie on each side of the first signal line211, respectively. The bottom surface of the second substrate22connects to a multi-layer substrate25where other circuitry layout is placed. The first and second parallel-connected capacitor devices23and24both could be open stubs, a plurality of open stubs interconnected with others by wire bonding or ribbon bonding, or in the form of having at least one capacitor connected to a grounded open stub.

Please refer toFIG. 6of a top view of a fourth preferred embodiment according to the present invention. A coupling device2aincludes a first substrate21ahaving a first signal line211a, a second substrate having a second signal line (refer toFIG. 5), a first parallel-connected capacitor device23a, and a second parallel-connected capacitor device24aon each side of the first signal line211a. In the current embodiment, the first and second parallel-connected capacitor devices23aand24aare open stubs231aand241a, respectively, in order to save more space than the embodiment shown inFIG. 2. InFIG. 2, in the case that the open stub131atakes more space the space of the whole coupling device1aincreases as the result. The present embodiment divides the open stub131ainFIG. 2into two pieces of open stubs231aand241aplaced on each side of the first signal line211a, for the purpose of limiting the size of the entire coupling device2a.

Please refer toFIG. 7of a top view of a fifth preferred embodiment according to the present invention. A coupling device2bincludes a first substrate21bhaving a first signal line211b, a second substrate connected to the first substrate21band having a second signal line (refer toFIG. 5), and a first parallel-connected capacitor device23band a second parallel-connected capacitor device24bplaced on each side of the first signal line211b, respectively. The first and second parallel-connected capacitor devices23band24bare a plurality of open stubs231band241b, respectively. Those open stubs231band241bare interconnected with others through wire bonding or ribbon bonding. In doing so, at the time of adjusting the area of the first and second parallel-connected capacitor devices23band24bonly cutting down the number of those open stubs231band241bis required, providing a viable alternative to the fourth preferred embodiment according to the present invention shown inFIG. 5.

Please refer toFIG. 8of a top view of a sixth preferred embodiment according to the present invention. A coupling device2cincludes a first substrate21chaving a first signal line211c, a second substrate connected to the first substrate21cand having a second signal line (refer toFIG. 5), and a first parallel-connected capacitor device23cand a second parallel-connected capacitor device24cplaced on each side of the first signal line211b, respectively. The first and second parallel-connected capacitor devices23cand24care single capacitors233cand243cconnected to grounded open stubs234cand244c. One end of each of capacitors233cand243cconnects to the first signal line211cwhile the other end of those capacitors233cand243cconnects to grounded open stubs234cand244c. Those grounded open stubs233cand244ceach has at lest one through hole2341cand2441cconnected to the ground. The present preferred embodiment controls the value of capacitors233cand243cfor controlling the coupling effect, the return loss, and the isolation capacity thereof.

Please refer toFIGS. 9A and 9Bof schematic diagrams showing S-parameter curves of coupling devices according to the present invention and prior art, respectively. Both coupling devices have in put end, a coupling end, an output end, and an isolation end. The coupling device according to the present invention has a first, second, third, and fourth curves31,32,33, and34while its counterpart based on the prior art is with fifth, sixth, seventh, and eighth curves41,42,43, and44.

The second and third curves are from the coupling and output ends of the coupling device according to the present invention. From those two curves, the amount of coupling effect and output is substantially equal at the frequency of 2 GHz while their counterparts (the sixth and seventh curves42and43from coupling and output ends of the coupling device of the prior art) are not close to each other at the same 2 GHz frequency, failing to meet the goal of having the amount of the coupling effect and output substantially equal.

The first and fifth curves show inputs of coupling devices according to the present invention and prior art. At the frequency of 2 GHz, the return loss for the coupling device according to the present invention is minus 32 db but is minus 15 db in the case of the coupling device based on the prior art. As the result, the present coupling device does improve the return loss.

The fourth and eighth curves34and44come from isolation ends of coupling devices according to the present invention and prior art, respectively. At the frequency of 2 GHz, the amount of isolation capacity is minus 31 db in the coupling device according to the present invention while the coupling device according to the prior art has the isolation capacity stay at minus 17.5 db. Above two curves show the difference in the isolation capacity between the coupling device according to the prior art and present invention, which effectively improve the performance of the isolation capacity.

In contrast to prior art coupling device, the coupling device according to the present invention incorporates a parallel-connected capacitor device to the ground for improving the return loss and isolation capacity and making the coupling effect and the amount of output reach to a level as expected. With the aforementioned characteristic, the present invention makes transmitting speeds in the first and second signal lines remain substantially the same so as to achieve better high frequency characteristics.