KR100941088B1 - Semiconductor device using near-end crosstalk, method of manufacturing a semicontuctor device, method of operating a semiconductor device and communication system - Google Patents

Abstract

The semiconductor device includes a substrate, a semiconductor chip, a first transmission line and a second transmission line. The semiconductor chip generates a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal. The first transmission line receives the first signal from the semiconductor chip. The second transmission line is formed on the substrate so as to be parallel with the first transmission line and open at an end and having a length corresponding to half of the wavelength. Near-end crosstalk is generated in the first transmission line by the second transmission line, thereby efficiently compensating for high frequency attenuation.

Near-end crosstalk, NEXT

Description

Semiconductor device, method of manufacturing semiconductor device, method of driving semiconductor device, and communication system using near-end crosstalk

The present invention relates to a semiconductor device, and more particularly, to a semiconductor device capable of compensating high frequency loss with a simple structure, a manufacturing method of a semiconductor device, a driving method of a semiconductor device, and a communication system.

Recently, with the development of digital signal transmission technology, digital signals are serialized and transmitted, and the transmission speed of digital signals is also very fast. Accordingly, transmission speeds of high-speed serial interfaces such as Serial Advanced Technology Attachment (SATA) and High-Definition Multimedia Interface (HDMI) have reached hundreds of Mbps and several Gbps. As the transmission speed increases, high frequency attenuation is intensified in the process of transmitting signals through a printed circuit board (PCB), a cable, and a connector. The resistance per unit length by the parallel plate transmission line according to the frequency is expressed by Equation 1.

Where σ represents the conductivity of the channel (5.8 * 10 ⁷ ohm / m for copper) and W represents the width of the transmission line. In Equation 1, the resistance value is represented as a function of frequency, and it can be seen that the value increases as the frequency increases. As such, the higher the frequency component, the higher the frequency-dependent loss, which causes higher loss. The higher data rate includes more high-frequency signals, so the higher the data rate, the higher the data rate. Becomes even worse. In other words, as the data transmission rate increases, high frequency attenuation becomes more severe. Recently, a pre-emphasis technique has been used to compensate for such high frequency attenuation and improve signal integrity.

1 is a block diagram showing a communication system for transmitting a conventional high speed data.

Referring to FIG. 1, the communication system 100 includes a transmitter 110, a receiver 120, and a transmission line 130, and the transmitter 110 includes a core 111 and a preemphasis circuit 113. .

The core 111 generates a signal and delivers it to the preemphasis circuit 113. The pre-emphasis circuit 113 amplifies the high frequency component of the signal generated by the core 111. The signal amplified by the high frequency component is transmitted to the receiver 120 through the transmission line 130. Although a high frequency attenuation occurs when a signal is transmitted through the transmission line 130, a high frequency attenuation is compensated by amplifying the high frequency component of the signal transmitted by the pre-emphasis circuit 113, that is, by pre-emphasis.

FIG. 2A is a waveform diagram showing signals before and after pre-emphasis, and FIG. 2B is a diagram showing gains with frequency during signal transmission before and after pre-emphasis.

Referring to FIG. 2A, the pre-emphasis pre-signal S1 includes high frequency components 141a, 142a, 143a, 144a, 145a, and 146a. Before transmitting the pre-emphasis signal S1, the high frequency components 141a, 142a, 143a, 144a, 145a, and 146a are amplified to compensate for the high frequency attenuation. The pre-emphasis signal S2 after the high frequency components 141a, 142a, 143a, 144a, 145a, and 146a are amplified includes the amplified high frequency components 141b, 142b, 143b, 144b, 145b, and 146b. Signal integrity can be improved by transmitting signal S2 after pre-emphasis.

Referring to FIG. 2B, when looking at the transmission loss line 151 representing the gain according to the frequency when high speed data is transmitted, it can be seen that the higher the frequency signal is, the more negative gain, i.e., the attenuation, is. In order to compensate for the attenuation of the high frequency signal, the high frequency signal may be amplified. Looking at the pre-emphasis line 152 that amplifies the signal according to frequency, it can be seen that the pre-emphasis is to amplify the signal by increasing the positive gain, that is, the gain degree, as the high-frequency signal. Looking at the transmission loss line 153 after the pre-emphasis indicating the gain according to the frequency when the pre-emphasized signal is transmitted, the high-frequency attenuation when the signal is transmitted is reduced when the pre-emphasized signal is transmitted. Able to know.

Conventional such pre-emphasis circuits have been implemented as circuits on semiconductors using active or passive devices such as high-pass filters, inductive terminations, and the like. However, these pre-emphasis circuits have a complicated structure, which requires a lot of effort in circuit design, occupies a large area on the semiconductor substrate, and consumes high manufacturing costs.

In order to solve the above problems, an object of the present invention is to provide a semiconductor device capable of amplifying high frequency components of a signal with a simple structure.

Moreover, an object of this invention is to provide the manufacturing method of the semiconductor device which can manufacture the semiconductor device which can amplify the high frequency component of a signal at low cost.

Another object of the present invention is to provide a method of driving a semiconductor device capable of driving a semiconductor device capable of amplifying a high frequency component of a signal.

Another object of the present invention is to provide a communication system capable of amplifying high frequency components of a signal with a simple structure.

In order to achieve the above object, a semiconductor device according to an embodiment of the present invention includes a substrate, a semiconductor chip, a first transmission line and a second transmission line.

The semiconductor chip is mounted on the substrate and generates a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal. The first transmission line is electrically connected to the semiconductor chip, is formed on the substrate, and receives the first signal from the semiconductor chip. The second transmission line is electrically connected to the semiconductor chip, and is formed on the substrate to be parallel to the first transmission line, open at an end, and have a length corresponding to half of the wavelength. Is provided with the second signal. The first signal and the second signal may each be a digital signal.

The first transmission line and the second transmission line may each be one of a microstrip, a stripline, or a coaxial cable. The semiconductor chip may include a first output driver for outputting the first signal and a second output driver for outputting the second signal to have a greater amplitude than the first signal.

In the method of manufacturing a semiconductor device according to an embodiment of the present invention for achieving the above object, a semiconductor chip is mounted on a substrate, a first transmission line is formed on the substrate, and the semiconductor chip and the first transmission line are connected. And a second transmission line parallel to the first transmission line and open at an end thereof on the substrate, and electrically connecting the semiconductor chip and the second transmission line. The second transmission line may be formed to have a length corresponding to half of the wavelength of the signal transmitted from the first transmission line.

In a method of driving a semiconductor device according to an embodiment of the present invention for achieving the above object, a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal are generated, A first signal is provided, and the second signal is provided to a second transmission line parallel to the first transmission line and open at an end and having a length corresponding to half of the wavelength.

In order to achieve the above object, a communication system according to an embodiment of the present invention includes a transmitter, a first transmission line, a second transmission line and a receiver.

The transmitter generates a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal. The first transmission line is electrically connected to the transmitter and receives the first signal from the transmitter. The second transmission line is electrically connected to the transmitter, is parallel to the first transmission line, has an open end, has a length corresponding to half of the wavelength, and receives the second signal from the transmitter. . The receiver receives the first signal from the first transmission line. The first signal and the second signal may each be a digital signal.

The first transmission line and the second transmission line may each be any one of a microstrip, a stripline, and a coaxial cable.

The semiconductor device, the method of manufacturing the semiconductor device, the method of driving the semiconductor device, and the communication system according to the embodiments of the present invention as described above use high-frequency components of a signal transmitted in a simple structure using near-end crosstalk. It can be amplified efficiently.

In addition, the semiconductor device, the method of manufacturing the semiconductor device, the method of driving the semiconductor device, and the communication system according to the embodiments of the present invention can reduce the design cost and manufacturing cost of the semiconductor device for efficiently amplifying the high frequency component of the signal.

With respect to the embodiments of the present invention disclosed in the text, specific structural to functional descriptions are merely illustrated for the purpose of describing embodiments of the present invention, embodiments of the present invention may be implemented in various forms and It should not be construed as limited to the embodiments described in.

As the inventive concept allows for various changes and numerous modifications, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between. Other expressions describing the relationship between components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring", should be interpreted as well.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is described, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. .

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. The same reference numerals are used for the same elements in the drawings, and duplicate descriptions of the same elements are omitted.

3 is a block diagram illustrating a communication system according to an embodiment of the present invention.

Referring to FIG. 3, the communication system 200 includes a transmitter 210, a receiver 220, a first transmission line 231, and a second transmission line 232. The transmitter 210 includes a core 211.

The communication system 200 may be a communication system for transmitting data at high speed, the transmitter 210 may transmit a signal at high speed, and the receiver may receive a signal transmitted at high speed. The core 211 included in the transmitter 210 generates first and second signals SS1 and SS2 to be transmitted to the receiver 220 such as data or clock. The core 211 is electrically connected to the first transmission line 231 and the second transmission line 232, respectively, and the generated first and second signals SS1 and SS2 are connected to the first transmission line 231 and the second transmission line. Output to 232 respectively. That is, the first signal SS1 input to the first transmission line 231 and the signal second SS2 input to the second transmission line 232 are the same signal. Here, the same signal means that the phases, traveling speeds, and wavelengths of the two signals SS1 and SS2 are the same. That is, according to the exemplary embodiment, the first signal SS1 and the second signal SS2 have substantially the same phase, traveling speed, wavelength, and amplitude, or the first signal SS1 and the second signal SS2. May have substantially the same phase, travel speed and wavelength, and may have different amplitudes. As the first transmission line 231 receives the first signal SS1 from the transmitter 210 and outputs the first signal SS1 to the receiver 220, the transmitter 210 may transmit the first signal SS1 to the receiver 220. When the first transmission line 231 transmits the first signal SS1, a frequency dependent loss may occur to attenuate high frequency components of the first signal SS1. However, such a high frequency attenuation phenomenon may be sufficiently compensated by near-end crosstalk generated in the second transmission line 232.

The second transmission line 232 is disposed in parallel with the first transmission line 231, and the second transmission line 232 has the same second signal SS2 as the first signal SS1 transmitted by the first transmission line 231. Is input. Here, the parallel between the second transmission line 232 and the first transmission line 231 means that the portion of the first transmission line 231 corresponding to the length L of the second transmission line 232 is parallel to the second transmission line 232. The first transmission line 231 may not extend in the same direction as the second transmission line 232 except for the portion of the first transmission line 231. One end 233 of the second transmission line 232 is electrically connected to the core 211 included in the transmitter 210, and the other end 234 is opened. At the other open end 234 of the second transmission line 232, the second signal SS2 input to the second transmission line 232 may be substantially reflected. The second transmission line 232 has a length L corresponding to substantially half of the wavelength of the second signal SS2. According to an embodiment, the first and second signals SS1 and SS2 are digital signals and the second transmission line 232 corresponds to one bit of the first and second signals SS1 and SS2. It may have a length (L) corresponding to half of the wavelength. At the other open end 234 of the second transmission line 232 having the length L corresponding to half of the wavelength of the second signal SS2, the second signal SS2 is substantially reflected and the reflected second The signal SS2 travels toward one end 233 and provides the first transmission line 231 with near-end crosstalk noise having the same phase as the reflected second signal SS2. On the other hand, the narrower the distance D between the first transmission line 231 and the second transmission line 232 disposed in parallel, the greater the noise generated by the near-end crosstalk. Due to the characteristics of the near-end crosstalk, the near-end crosstalk noise corresponding to twice the length L of the second transmission line 232 is generated in the first signal SS1 transmitted from the first transmission line 231. That is, the noise corresponding to one wavelength or one bit is provided to the first signal SS1. Here, since the first signal SS1 and the second signal SS2 are the same signal, a component corresponding to one wavelength or one bit of the first signal SS1, that is, a high frequency component, is amplified. Therefore, the second transmission line 232 disposed in parallel with the first transmission line 231 and having a half-wavelength of the transmitted signal, and the terminal 234 is open, can amplify the high frequency component of the signal simply and efficiently. have.

4 is a perspective view illustrating a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 4, the semiconductor device 300 includes a substrate 310, a semiconductor chip 320, a first transmission line 331, and a second transmission line 332.

The semiconductor chip 320, the first transmission line 331, and the second transmission line 332 are formed on the substrate 310. According to an embodiment, the substrate 310 is a circuit board having an electrical connection form of a signal. A printed circuit board (PCB), a ball grid array (BGA), a land grid array (LGA), or a low temp. -fired ceramics). The first pad 321 of the semiconductor chip 320 may be electrically connected to the third pad 351 connected to the first transmission line 331 through the first bonding wire 341. The second pad 322 may be electrically connected to the fourth pad 352 connected to the second transmission line 332 through the second bonding wire 342. In some embodiments, both ends of the first transmission line 331 and one end of the second transmission line 332 connected to the fourth pad 352 may be terminated in 50 ohms. That is, 50 ohm termination resistors may be connected to both ends of the first transmission line 331, and 50 ohm termination resistors may be connected only to one end of the second transmission line 332 connected to the fourth pad 352.

The semiconductor chip 320 outputs a first signal to the first transmission line 331 through the first pad 321, the first bonding wire 341, and the third pad 351, and the second pad 322, The second signal is output to the second transmission line 332 through the second bonding wire 342 and the fourth pad 352. The first signal and the second signal are substantially the same signal. According to an embodiment, the semiconductor chip 320 may include a first output driver for outputting the first signal and a second output driver for outputting the second signal, and the first output driver and the second output. The driver may output the first signal and the second signal having different amplitudes, respectively. Even if the amplitudes of the first signal and the second signal are different, the phase, traveling speed, and wavelength are substantially the same. Meanwhile, the magnitude of the near-end crosstalk noise may vary according to the amplitude of the second signal. The first signal may be transmitted to another semiconductor chip on the substrate 310 or a circuit outside the substrate 310 through the first transmission line 331. High frequency components may attenuate when the first signal is transmitted through the first transmission line 331, and high frequency attenuation may be more pronounced when the first signal is transmitted at high speed.

The second transmission line 332 is disposed in parallel with the first transmission line 331. According to an embodiment, the first transmission line 331 may have a shape such as a bent line, but a portion corresponding to the length L of the second transmission line 332 has a shape substantially extending only in the first direction. . In addition, the second transmission line 332 has a shape extending substantially in the first direction, and is formed to be spaced apart from the first transmission line 331, whereby the first transmission line 331 and the second transmission line 332 are substantially formed. Arranged in parallel. As the distance D between the first transmission line 331 and the second transmission line 332 is narrower, the noise generated by the near-end crosstalk may increase, and it is preferable that the thickness D is less than six times the thickness of the substrate 310.

One end of the second transmission line 332 is directly connected to the fourth pad 352, and the other end thereof is opened. At the open end of the second transmission line 332, substantially all of the second signals input to the second transmission line 332 may be reflected. The second transmission line 332 has a length L corresponding to substantially half of the wavelength of the second signal. According to an embodiment, the first and second signals are digital signals, and the second transmission line 332 may have a length L corresponding to one half of a wavelength corresponding to one bit of the first and second signals. have. At the open end of the second transmission line 332 having a length L corresponding to half of the wavelength of the second signal, the second signal is substantially reflected, and the reflected second signal is a fourth pad ( Proceeding toward the terminal directly connected to 352, the near-end crosstalk noise having the same phase as the reflected second signal is provided to the first transmission line 331. Due to the nature of the near-end crosstalk, the near-end crosstalk noise corresponding to twice the length L of the second transmission line 332 is generated in the first signal transmitted from the first transmission line 331. That is, noise corresponding to one wavelength or one bit is provided to the first signal. Here, since the first signal and the second signal are the same signal, an effect that a component corresponding to one wavelength or one bit of the first signal, that is, a high frequency component, is amplified. Therefore, the second transmission line 332, which is disposed in parallel with the first transmission line 331, has a length of half the wavelength of the transmitted signal, and has an open terminal, can amplify the high frequency component of the signal simply and efficiently.

5 is a waveform diagram illustrating a signal before preemphasis and a signal pre-emphasized in the semiconductor device according to an exemplary embodiment of the present inventive concept.

4 and 5, the signal 402 pre-emphasized in the semiconductor device 300 according to the exemplary embodiment of the present invention is amplified by a high frequency component compared to the signal 401 before the pre-emphasis. have. In the example of FIG. 5, the waveform when a 3.4-Gbps signal is amplified by near-end crosstalk is shown. Here, since the length of the second transmission line 332 corresponds to half of the wavelength of the transmitted signal, it is calculated as in Equation 2.

Where L represents the length of the second transmission line 332, v represents the traveling speed of the signal, and f represents the frequency of the signal. When the length of the second transmission line 332 used in the example of FIG. 5 is calculated, the traveling speed of the signal is about 1.6 * 108 m / s and the frequency is 3.4 * 10 ⁹ hz when the substrate 300 is a PCB. The length of the second transmission line 332 may be about 23.5 mm. That is, when a signal of 3.4 Gbps is transmitted through the first transmission line 331, by inputting the same signal to the second transmission line 332 having a length of about 23.5 mm, it is possible to simply and efficiently amplify the high frequency component of the signal. Can be.

FIG. 6A is an eye diagram illustrating a waveform after transmission of a non-pre-emphasized signal, and FIG. 6B illustrates a waveform after transmission of a pre-emphasized signal in a semiconductor device according to an embodiment of the present invention. Indicating eye diagram.

6A and 6B, a signal in which the signal integrity of the signal shown in FIG. 6B, which is a signal after the pre-emphasized signal is transmitted in the semiconductor device according to an embodiment of the present invention, is not preemphasized. It can be seen that the signal is improved from the signal shown in FIG. 6A after the transmission. 6A and 6B show simulation results when a 3.4 Gbps signal is transmitted through a 1 m transmission line. In the example of FIG. 6B, an auxiliary transmission line parallel to the transmission line having a length of about 23.5 mm was used, and the transmission line and the auxiliary transmission line were spaced about 0.1 mm apart. In this case, a coupling coefficient indicating the extent to which near-end crosstalk occurs is about 0.16. Meanwhile, when the distance between the transmission line and the auxiliary transmission line is narrowed, the crosstalk coefficient may be larger than 0.16. Referring to the eye-height and timing jitter of FIGS. 6A and 6B, the eye height 502b and time noise 501b of the signal after the pre-emphasized signal of FIG. 6B is transmitted are shown in FIG. It can be seen that the non-emphasized signal of 6a is higher and smaller than the eye height 502a and the time noise 501a, respectively, after the signal is transmitted. Therefore, it can be seen that the signal integrity is improved when the pre-emphasized signal is transmitted in the semiconductor device 300 having the simple structure of FIG. 4.

On the other hand, one of ordinary skill in the art will recognize that each of the transmission lines may be a microstrip, a stripline, a coaxial cable, or the like. Here, microstrip refers to a transmission line in which a dielectric substrate is formed on one grounded conducting plane, and a metal strip is formed on the dielectric substrate, and a stripline A dielectric substrate is formed between two parallelly arranged grounded conductor planes, and means a transmission line formed with a metal strip spaced apart from each of the grounded conductor planes in the dielectric substrate.

Since the present invention can efficiently compensate for high frequency attenuation using near-end crosstalk with a simple structure, it can be usefully used for high-speed data communication. In particular, the semiconductor device according to embodiments of the present invention may be more usefully used in a high speed interface system in which digital signals are transmitted at high speed.

While the invention has been described above with reference to preferred embodiments, those skilled in the art will be able to make various modifications and changes to the invention without departing from the spirit and scope of the invention as set forth in the claims below. I will understand.

1 is a block diagram showing a communication system for transmitting a conventional high speed data.

2A is a waveform diagram illustrating signals before and after preemphasis.

FIG. 2B is a diagram showing a gain diagram according to frequency during signal transmission before and after pre-emphasis.

3 is a block diagram illustrating a communication system according to an embodiment of the present invention.

4 is a perspective view illustrating a semiconductor device according to an embodiment of the present invention.

5 is a waveform diagram illustrating a signal before preemphasis and a signal pre-emphasized in the semiconductor device according to an exemplary embodiment of the present inventive concept.

6A is an eye diagram showing the waveform after transmission of a non-preemphasized signal.

6B is an eye diagram illustrating a waveform after transmission of a pre-emphasized signal in a semiconductor device according to an embodiment of the present invention.

Description of the main parts of the drawing

200: communication system 210: transmitter

211: core 220: receiver

231 and 331: first transmission line 232 and 332: second transmission line

300: semiconductor device 310: substrate

320: semiconductor chip 341, 342: bonding wire

321, 322, 341, 342: pad

Claims (14)

Board; A semiconductor chip mounted on the substrate and generating a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal, the semiconductor chip having a first pad and a second pad; A first transmission line electrically connected to the first pad of the semiconductor chip, formed on the substrate, and receiving the first signal from the semiconductor chip; And Electrically connected to the second pad of the semiconductor chip, formed on the substrate to be parallel to the first transmission line and open at an end, and having a length corresponding to half of the wavelength; And a second transmission line receiving the second signal. The method of claim 1, wherein the first signal and the second signal, Each semiconductor device is a digital signal. The method of claim 1, wherein the first transmission line and the second transmission line, A semiconductor device, characterized in that each of the microstrip (microstrip). The method of claim 1, wherein the first transmission line and the second transmission line, A semiconductor device, characterized in that each of the stripline (stripline). The method of claim 1, wherein the first transmission line and the second transmission line, A semiconductor device, each of which is a coaxial cable. The method of claim 1, wherein the semiconductor chip, A first output driver for outputting the first signal; And And a second output driver for outputting the second signal to have a greater amplitude than the first signal. Mounting a semiconductor chip having a first pad and a second pad on a substrate; Forming a first transmission line on the substrate; Electrically connecting the first pad and the first transmission line of the semiconductor chip; Forming a second transmission line on the substrate so as to be parallel to the first transmission line and open at an end thereof; And And electrically connecting the second pad and the second transmission line of the semiconductor chip. The method of claim 7, wherein the forming of the second transmission line, And the second transmission line is formed to have a length corresponding to half of the wavelength of the signal transmitted from the first transmission line. Generating a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal; Providing the first signal to a first transmission line through a first pad in a semiconductor chip; And Providing the second signal to a second transmission line in the semiconductor chip, the second transmission line being parallel to the first transmission line through a second pad and having an open end and having a length corresponding to half of the wavelength. Method of driving. A transmitter electrically connected to the first pad and the second pad, the transmitter generating a first signal and a second signal having the same phase, traveling speed, and wavelength as the first signal; A first transmission line electrically connected to the first pad and receiving the first signal from the transmitter; A second transmission line electrically connected to the second pad, parallel to the first transmission line, open at an end, having a length corresponding to half of the wavelength, and receiving the second signal from the transmitter ; And And a receiver for receiving the first signal from the first transmission line. The method of claim 10, wherein the first signal and the second signal, A communication system, each of which is a digital signal. The method of claim 10, wherein the first transmission line and the second transmission line, And each microstrip. The method of claim 10, wherein the first transmission line and the second transmission line, Wherein each is a stripline. The method of claim 10, wherein the first transmission line and the second transmission line, A communication system, characterized in that each of the coaxial cable (coaxial cable).

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