JP5274332B2 - Microwave semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a microwave semiconductor device, for securing not only high stability by making a resistor absorb useless microwave generated in the semiconductor element but also securing high reliability even if a resistor is burnt. <P>SOLUTION: An input matching circuit 3 includes a first transmission line 7 and two second transmission lines 8a, 8b disposed in parallel. Between the two second transmission lines 8a, 8b, a resistor 18a is provided for connecting a point (a) and a point (b) respectively located on the two second transmission lines 8a, 8b with different distances from the signal input ends of the two second transmission lines 8a, 8b. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a microwave semiconductor device used in a radar device, a microwave communication device, or the like.

  A microwave semiconductor device used in a radar device, a microwave communication device, or the like includes a semiconductor element that realizes an amplifier, an oscillator, a mixer, and the like, and matching circuits provided on the input side and output side of the semiconductor element, respectively. (For example, see Patent Document 1).

  In recent years, in response to the demand for higher performance and higher frequency of radar devices, microwave communication devices, etc., the semiconductor elements in the microwave semiconductor devices used therein have very high frequencies such as microwave band and millimeter wave band. A band having a sufficient gain has also been used.

  However, in a semiconductor device operating in the microwave band or the millimeter wave band, when an unnecessary microwave with a thermal noise level generated by the semiconductor element itself is fed back to the input side, unnecessary oscillation occurs in a certain frequency region, and the operation However, the frequency region in which the operation becomes unstable tends to be widened as the performance of the semiconductor element increases.

  Therefore, in order to configure the microwave semiconductor device, a device for avoiding unnecessary oscillation and unstable operation over a wide band from low frequency to high frequency is required. In Patent Document 1 as a means for achieving stabilization, a configuration in which a resistor is loaded over the entire line width in the direction perpendicular to the propagation direction of the microwave on the input transmission line forming the input matching circuit of the semiconductor element. Is disclosed.

  According to this configuration, since the microwave propagating through the input transmission line toward the input terminal of the semiconductor element is absorbed and attenuated by the resistor interposed in the middle, the microwave is fed back to the propagating microwave from the semiconductor element. Therefore, the unnecessary microwave with the noise level mixed in is reduced to the extent that the semiconductor element is not sensitive, and a highly stable microwave semiconductor device can be obtained.

JP 2003-188665 A

  By the way, conventionally, HEMT (high electron mobility transistor) or FET (field effect transistor) made of GaAs (gallium arsenide) or the like is used as the semiconductor element, but HEMT or FET made of GaN (gallium nitride) appears. I have done it. For this reason, there is an increasing demand for higher output in microwave semiconductor devices in addition to higher frequencies. In particular, GaN-HEMTs and FETs are expected to develop microwave semiconductor devices for TWTA (traveling wave tube amplifier) replacement because the output per unit gate width is one digit higher than GaAs-HEMTs and FETs. ing.

  Such a microwave semiconductor device for TWTA replacement requires a larger input signal than a conventional microwave semiconductor device in order to obtain a higher output. Then, in the structure of the stabilization means disclosed in the above-mentioned Patent Document 1, the power consumed by the resistor loaded in series with the input terminal of the semiconductor element also increases, which causes a problem that the resistor burns out. To do. If the resistor burns out, it becomes impossible to supply an input signal to the semiconductor element, and the function of the microwave semiconductor device is lost.

  In order to avoid this, only the electric power considering the electric power resistance of the resistor can be handled, and it becomes difficult to realize a microwave semiconductor device with higher output. On the other hand, when the area of the resistor is increased in order to improve the power resistance of the resistor, the input signal consumed by the resistor increases, and thus the performance of the microwave semiconductor device is significantly deteriorated. there were.

  The present invention has been made in view of the above, and allows the resistor to absorb unnecessary microwaves generated in the semiconductor element to achieve high stability, and ensures high reliability even if the resistor burns out. An object of the present invention is to obtain a microwave semiconductor device.

  In order to achieve the above-described object, the present invention provides a microwave semiconductor device in which matching circuits are respectively arranged on an input side and an output side of a semiconductor element, wherein the matching circuits on the input side are two or more arranged in parallel. Between the two transmission lines adjacent to each other between the two transmission lines, the distance between the two transmission lines being different from the signal input end of the two transmission lines. It is characterized in that a resistor is provided.

  According to the present invention, since a potential difference is generated between two points having different distances from the signal input end on two adjacent transmission lines, a part of the microwave input signal propagating through the two transmission lines. Is consumed by the resistor. Therefore, unnecessary microwaves generated in the semiconductor element superimposed on the microwave input signals propagating through the two transmission lines are partially absorbed by the resistor, and unnecessary microwaves input from the two transmission lines. This level is reduced to the extent that the semiconductor element is insensitive, so that it is possible to realize a microwave semiconductor device that can be highly stabilized.

  In addition, even if the resistor burns out, the input signal can be supplied to the semiconductor element, so that all functions are not lost and the stability performance is only slightly degraded. There is also an effect that a semiconductor device can be realized.

1A and 1B are schematic external views showing the configuration of the microwave semiconductor device according to the first embodiment of the present invention. FIG. 1A is a plan view and FIG. 1B is a side view. FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the microwave semiconductor device shown in FIG. FIG. 3 is a characteristic diagram illustrating the stability of the microwave semiconductor device shown in FIG. FIG. 4 is a schematic external view showing the configuration of the microwave semiconductor device according to the second embodiment of the present invention. FIG. 5 is a schematic external view showing the configuration of the microwave semiconductor device according to the third embodiment of the present invention. FIG. 6 is an equivalent circuit diagram showing an electrical configuration of the microwave semiconductor device shown in FIG. FIG. 7 is a schematic external view showing the configuration of the microwave semiconductor device according to the fourth embodiment of the present invention.

  Embodiments of a microwave semiconductor device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1A and 1B are schematic external views showing the configuration of the microwave semiconductor device according to the first embodiment of the present invention. FIG. 1A is a plan view and FIG. 1B is a side view. In the first embodiment and the second to fourth embodiments described below, the microwave semiconductor device is described with an amplifier for TWTA replacement in mind, but it can be similarly applied to an oscillator, a mixer, and the like. is there.

  In FIG. 1, a microwave semiconductor device 1a includes a semiconductor element 2, and an input matching circuit 3 and an output matching circuit 4 arranged on the input side and the output side of the semiconductor element 2, respectively. These are mounted on a metal carrier 5.

  The semiconductor element 2 is a GaN-HEMT, FET, or the like that can achieve high output in addition to high frequency. The input matching circuit 3 is a circuit for matching the signal source impedance with the input impedance of the semiconductor element 2. The output matching circuit 4 is a circuit that matches the output impedance of the semiconductor element 2 and the load impedance.

  The input matching circuit 3 includes a dielectric substrate 6 whose lower surface is fixed on the metal carrier 5, a first transmission line 7 formed on the upper surface of the dielectric substrate 6, and two parallel second transmission lines. 8a and 8b.

  The first transmission line 7 is provided with an input terminal 9 on one end side, and two second transmissions arranged in parallel on the other end side for microwave and millimeter wave signals input to the input terminal 9. This is a line for distributing and transmitting to the lines 8a and 8b.

  The second transmission lines 8 a and 8 b are band-like conductor layers on both sides of the rectangular deletion portion 10 provided on the conductor layer on the other end side of the first transmission line 7. In other words, the line lengths of the second transmission lines 8a and 8b are the lengths in the longitudinal direction of the rectangular deletion part 10, and the interval between the second transmission lines 8a and 8b is short of the rectangular deletion part 10. The length of the direction.

  A connection terminal 11 is provided on the open end side (semiconductor element 2 side) of the second transmission lines 8a and 8b. The semiconductor element 2 has two or more input terminals and output terminals. FIG. 1 shows a case where two input terminals of the semiconductor element 2 are connected to the connection terminal 11 using the metal thin wires 12a and 12b on the open end side of the second transmission lines 8a and 8b. The two input terminals also exist between the open ends of the second transmission lines 8a and 8b. For this reason, the connection terminal 11 is provided in an elongated shape region that short-circuits between the open ends of the second transmission lines 8a and 8b.

  The output matching circuit 4 includes a dielectric substrate 13 whose lower surface is fixed on the metal carrier 5 and a third transmission line 14 formed on the upper surface of the dielectric substrate 13. On the input end side (semiconductor element 2 side) of the third transmission line 14, a connection terminal 15 having an elongated shape region that extends over the entire width of the third transmission line 14 is provided. In the illustrated example, the two output terminals of the semiconductor element 2 are connected to the connection terminal 15 using fine metal wires 16a and 16b. An output terminal 17 is provided on the output end side of the third transmission line 14. An amplified signal of the input signal amplified by the semiconductor element 2 is output from the output terminal 17 to the outside.

  In the microwave semiconductor device configured as described above, in the first embodiment, signal input to the second transmission lines 8a and 8b is performed in the rectangular deletion unit 10 between the second transmission lines 8a and 8b. A resistor 18a having a length substantially equal to the distance L between the points a and b between the points a and b on the second transmission lines 8a and 8b having different distances from the ends is rectangular. It is loaded in parallel with the longitudinal direction of the deletion unit 10. One end of the resistor 18a is pattern-connected to a point a on the second transmission line 8a, and the other end is pattern-connected to a point b on the second transmission line 8b.

  Next, FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the microwave semiconductor device shown in FIG. In FIG. 2, the input matching circuit 3 has a configuration in which a first transmission line 7 and two second transmission lines 8a and 8b connected in parallel are connected to an input terminal 9 in this order. It can be expressed by an equivalent circuit in which a resistor 18a is loaded between a point a and a point b that are separated by a distance L on the two second transmission lines 8a and 8b.

  The inductor 19 that connects between the input matching circuit 3 and the input terminal (gate terminal) of the semiconductor element 2 is an inductance component of the thin metal wires 12a and 12b shown in FIG. Similarly, the inductor 20 that connects between the output terminal (drain terminal) of the semiconductor element 2 and the output matching circuit 4 is an inductance component of the thin metal wires 16a and 16b shown in FIG. The output matching circuit 4 can be represented by a third transmission line 14 that connects the inductor 20 and the output terminal 17.

  In the equivalent circuit shown in FIG. 2, the characteristic impedance and length of each of the first transmission line 7 and the two second transmission lines 8a and 8b constituting the input matching circuit 3 are the semiconductor elements including the inductor 19. 2 is selected so as to match the impedance of a signal source (not shown) to which the input terminal 9 is connected.

  Similarly, the characteristic impedance and line length of the third transmission line 14 constituting the output matching circuit 4 match the output impedance of the semiconductor element 2 including the inductor 20 and the impedance of a load (not shown) connected to the output terminal 17. Have been selected to let.

  In this way, the first transmission line 7, the second transmission lines 8 a and 8 b, and the third transmission line 14 are input from the input terminal 9 by appropriately selecting each characteristic impedance and each line length. The input signal is equally distributed to the second transmission lines 8 a and 8 b via the first transmission line 7, supplied to the semiconductor element 2, amplified by the semiconductor element 2, and passed through the third transmission line 14. And output from the output terminal 17.

  Here, when the input signal equally distributed in the first transmission line 7 passes through the second transmission lines 8a and 8b, the potential difference between the points a and b of the second transmission lines 8a and 8b. Therefore, a part of the input signal is consumed by the resistor 18a. At this time, when the distance L is zero, there is no potential difference between the point a and the point b, so that there is no input signal consumed by the resistor 18a. On the other hand, when the distance L is ½ wavelength in the required band, the potential difference between the point a and the point b is the highest, so that the input signal consumed by the resistor 18a is maximized.

  Thus, since the input signal consumed by the resistor 18a depends on the distance L between the points a and b, the resistance value of the resistor 18a is constant by appropriately selecting the distance L. Even if it exists, the magnitude | size of the input signal consumed with the resistor 18a is controllable.

  Conversely, the above can cause the resistor 18a to absorb unnecessary microwaves generated in the semiconductor element 2 leaking into the input signal propagating through the second transmission lines 8a and 8b, and the amount absorbed. Can also be controlled. Therefore, the resistor 18a loaded between the second transmission lines 8a and 8b in the microwave semiconductor device 1a according to the first embodiment and the transmission in the direction perpendicular to the microwave propagation direction in the conventional microwave semiconductor device. The resistor loaded on the track has the same function.

  FIG. 3 is a characteristic diagram illustrating the stability of the microwave semiconductor device shown in FIG. In FIG. 3, the horizontal axis is the frequency, and the vertical axis is the stability coefficient. In short, the line with stability coefficient = 1 is a boundary line indicating whether or not to operate stably without oscillation under a certain load condition, and the area above stability coefficient = 1 is a stable operation region. The region below stability coefficient = 1 is the unstable operation region.

  FIG. 3 shows a stability characteristic (1) when no resistor is provided and a stability characteristic (2) when a resistor is provided. As shown in the stability characteristic (1), when no resistor is provided, the stable operation region is on the high frequency side, and the stability in the low frequency band is not good. On the other hand, as shown in the stability characteristic (2), when the resistor is provided, the stability coefficient is improved to 1 or more over a wide band from a low frequency band to a high frequency band across the required band. It can be understood that stabilization is possible.

  Thus, in the microwave semiconductor device 1a according to the first embodiment, the resistor 18a is provided between the point a and the point b having different distances from the signal input ends of the two second transmission lines 8a and 8b. By loading, it is superimposed on the input signal propagating through the second transmission lines 8a and 8b of the input matching circuit 3 as in the conventional microwave semiconductor device in which a resistor is loaded in series with the input terminal of the semiconductor element. The unnecessary microwave generated in the semiconductor element 2 can be absorbed, and the microwave semiconductor device can be stabilized.

  What should be noted at this time is that a part of the input signal is consumed by the resistor 18a in the microwave semiconductor device 1a according to the first embodiment, whereas in the conventional microwave semiconductor device, The point is that all of the input signal is consumed.

  Therefore, since the microwave semiconductor device 1a according to the first embodiment can supply a larger input signal than the conventional microwave semiconductor device, a GaN-HEMT or FET is used as the semiconductor element 2 in addition to higher frequency. It becomes possible to increase the output.

  At this time, in the microwave semiconductor device 1a according to the first embodiment, even if the resistor 18a burns out due to the supply of a large input signal, the input signal is transmitted to the semiconductor element 2 through the two second transmission lines 8a and 8b. Since it is input, there is no complete loss of function as in the conventional microwave semiconductor device, and the characteristics only need to be slightly deteriorated in terms of stabilization, and a highly reliable microwave semiconductor device can be realized.

  In the microwave semiconductor device 1a according to the first embodiment, the resistor 18a that can withstand the supply of a large input signal can be easily secured by increasing the area of the resistor 18a, and the area of the resistor 18a can be increased. The disappearance of the input signal due to the expansion can be compensated by the increase of the input signal, so that the characteristic degradation of the microwave semiconductor device due to the expansion of the area of the resistor 18a can be suppressed, and the microwave semiconductor with higher output can be suppressed. A device can be realized.

Embodiment 2. FIG.
FIG. 4 is a schematic external view showing the configuration of the microwave semiconductor device according to the second embodiment of the present invention. In FIG. 4, the same or similar components as those shown in FIG. 1 (Embodiment 1) are denoted by the same reference numerals. Here, the description will be focused on the portion related to the second embodiment.

  As shown in FIG. 4, in the microwave semiconductor device 1b according to the second embodiment, in the configuration shown in FIG. 1 (Embodiment 1), the rectangular deletion unit 10 has a resistor 18b instead of the resistor 18a. Is provided.

  The resistor 18b is loaded between the point a on the second transmission line 8a and the point b on the second transmission line 8b toward the short direction of the rectangular deletion part 10, and one end thereof is a thin metal wire. The other end is connected to the point b through the thin metal wire 23b.

  According to this configuration, the resistor 18b and the points a and b on the second transmission lines 8a and 8b are connected using the metal thin wires 23a and 23b. The distance L can be adjusted by arbitrarily selecting the point a and the point b.

  Therefore, in the second embodiment, in addition to obtaining the same operation and effect as in the first embodiment, it is possible to easily cope with variations in the characteristics of the semiconductor element 2, which is more than in the first embodiment. There is an advantage that the microwave semiconductor device can be highly stabilized.

Embodiment 3 FIG.
FIG. 5 is a schematic external view showing the configuration of the microwave semiconductor device according to the third embodiment of the present invention. In FIG. 5, the same reference numerals are given to components that are the same as or equivalent to the components shown in FIG. 1 (Embodiment 1). Here, the description will focus on the part related to the third embodiment.

  As shown in FIG. 5, in the microwave semiconductor device 1 c according to the third embodiment, the points a and b defined on the second transmission lines 8 a and 8 b are both ends in the longitudinal direction of the rectangular deletion unit 10. Resistors 18c having different lengths are provided in parallel with the longitudinal direction so as to connect between the short ends of both ends in the longitudinal direction of the rectangular deletion portion 10.

  Since the length in the longitudinal direction of the rectangular deletion part 10 is the line length of the second transmission lines 8a and 8b, the distance L between the point a and the point b is the line of the second transmission lines 8a and 8b. Become long. Therefore, the resistor 18c is loaded in parallel with the second transmission lines 8a and 8b.

  FIG. 6 is an equivalent circuit diagram showing an electrical configuration of the microwave semiconductor device shown in FIG. As shown in FIG. 6, the input matching circuit 3 can be expressed as a parallel circuit composed of a resistor 18 c and two second transmission lines 8 a and 8 b connected in cascade to the first transmission line 7. it can.

  In the microwave semiconductor devices 1a and 1b shown in the first and second embodiments, the second transmission lines 8a and 8b are so-called loss lines in which the resistors 18a and 18b are loaded in a partial section of the line length. Therefore, the reflection coefficient when the input matching circuit 3 side is viewed from the semiconductor element 2 is 1 at a frequency where the line length of the second transmission lines 8a and 8b is ½ wavelength. Therefore, when the input signal frequency is this frequency, unnecessary microwaves generated in the semiconductor element 2 cannot leak into the input matching circuit 3 side, and the resistors 18a and 18b are generated in the semiconductor element 1. Unnecessary microwaves cannot be absorbed.

  On the other hand, in the second transmission lines 8a and 8b in the microwave semiconductor device 1c according to the third embodiment, the resistor 18c is loaded over the entire length of the line, as shown in the first and second embodiments. In addition, the transmission line has a lower loss than the second transmission lines 8a and 8b in the microwave semiconductor devices 1a and 1b, and the reflection coefficient when the input matching circuit 3 side is viewed from the semiconductor element 2 is 1 or less even at the above frequency. It becomes. Therefore, unnecessary microwaves generated in the semiconductor element 2 can leak into the input matching circuit 3 side, and the resistor 18c absorbs unnecessary microwaves generated in the semiconductor element 2 superimposed on the input signal. be able to.

  Therefore, according to the third embodiment, a microwave semiconductor device 1c that is more stable than the first and second embodiments can be obtained. Of course, even if the resistor 18c is burned out, the function of the microwave semiconductor device 1c is not completely lost.

Embodiment 4 FIG.
FIG. 7 is a schematic external view showing the configuration of the microwave semiconductor device according to the fourth embodiment of the present invention. In FIG. 7, the same reference numerals are given to components that are the same as or equivalent to those shown in FIG. 5 (Embodiment 3). Here, the description will be focused on the portion related to the fourth embodiment.

  As shown in FIG. 7, in the microwave semiconductor device 1d according to the fourth embodiment, two rectangular deletion portions of the same size are formed on the conductor layer on the other end side (semiconductor element 2 side) of the first transmission line 7. By arranging 25 and 26 side by side in the line width direction of the first transmission line 7, three second transmission lines 8 a, 8 b, and 8 c arranged in parallel on the other end side of the first transmission line 7 are formed. Has been.

  Then, based on the same idea as shown in FIG. 5 (Embodiment 3), the points a and b defined on the second transmission lines 8a and 8b are both ends in the longitudinal direction of the rectangular deletion portion 25, and the second The points a and b defined on the transmission lines 8b and 8c are both ends in the longitudinal direction of the rectangular deletion portion 26. In the rectangular deletion portion 25, the resistor 18d connects the short ends at both ends in the longitudinal direction. In the rectangular deletion portion 26, the resistor 18e is provided in parallel to the longitudinal direction so as to connect the short ends at both ends in the longitudinal direction.

  As a result, among the two second transmission lines 8a, 8b, 8c arranged in parallel, the resistor 18d is loaded in parallel on the two adjacent second transmission lines 8a, 8b, and the two adjacent second transmission lines 8a, 8b, 8b are loaded. The resistor 18e is loaded in parallel on the two transmission lines 8b and 8c. As is obvious from the configuration shown in FIG. 7, the number of second transmission lines arranged in parallel can be increased to 4 or more.

  Also in the fourth embodiment, as described in the third embodiment, the resistors 18d and 18e can absorb unnecessary microwaves generated in the semiconductor element 2 superimposed on the input signal. A stable microwave semiconductor device 1d can be obtained. Even if the resistor 18c is burned out, the function of the microwave semiconductor device 1d is not completely lost.

  In addition, as the chip size of the semiconductor element 2 increases, the number of input terminals increases. In the fourth embodiment, three or more second transmission lines forming the input matching circuit 3 are arranged in parallel. Therefore, when the chip size of the semiconductor element 2 is increased and the number of input terminals is increased, the input signals are more uniformly supplied to the larger number of input terminals than in the first to third embodiments. Is possible. Therefore, even if the chip size of the semiconductor element 2 is increased, the semiconductor element 2 can be operated uniformly, and a microwave semiconductor device with higher output can be obtained.

  In this respect, the resistor loading configuration shown in the first and second embodiments has the difficulty as described in the third embodiment. Two transmission lines are arranged in parallel, and a rectangular deletion portion between two adjacent second transmission lines has a distance between two points shorter than the line length determined on the two adjacent second transmission lines. The same effect can be obtained by arranging a resistor to connect the two.

  As described above, in the microwave semiconductor devices shown in the first to fourth embodiments, a plurality of second transmission lines forming an input matching circuit are arranged in parallel, and two adjacent second transmission lines are arranged. Since the resistor is loaded between two points having different potentials, unnecessary microwaves generated in the semiconductor element leaking into the input matching circuit can be absorbed, and the microwave semiconductor device can be stabilized. .

  In addition, even if a large signal is input and the resistor burns out, the microwave semiconductor device does not lose its function completely, and the stability performance is only slightly degraded. A device can be obtained.

  Furthermore, since the resistor loaded between the two second transmission lines can have an area in consideration of withstand power, a microwave semiconductor device with higher output can be obtained.

  In addition, even if the chip size of the semiconductor element is increased, the semiconductor element can be operated uniformly. From this point as well, there is an advantage that a microwave semiconductor device with higher output can be realized.

  Although the first to fourth embodiments have been described with the amplifier as the microwave semiconductor device in mind, it is needless to say that the description can be applied to an oscillator, a mixer, a multiplier, and the like.

  As described above, the microwave semiconductor device according to the present invention can absorb the unnecessary microwave generated in the semiconductor element in the resistor and achieve high stability, and has high reliability even if the resistor burns out. It is useful as a microwave semiconductor device that can be secured, and is particularly suitable for increasing the output in addition to widening the bandwidth by using a GaN-HEMT or FET as a semiconductor element.

1a, 1b, 1c, 1d Microwave semiconductor device 2 Semiconductor element 3 Input matching circuit 4 Output matching circuit 5 Metal carrier 6, 13 Dielectric substrate 7 First transmission line 8a, 8b, 8c Second transmission line 9 Input Terminal 10, 25, 26 Rectangular deletion part 11, 15 Connection terminal 12 a, 12 b, 16 a, 16 b, 23 a, 23 b Metal thin wire 14 Third transmission line 17 Output terminal 18 a, 18 b, 18 c, 18 d, 18 e Resistor 19, 20 Inductor

Claims (2)

In the microwave semiconductor device in which matching circuits are respectively arranged on the input side and the output side of the semiconductor element,
The matching circuit on the input side is:
The two transmission lines comprising two or more transmission lines arranged in parallel, wherein two of the two or more transmission lines are different in distance from the signal input end of the two transmission lines between two adjacent transmission lines A microwave semiconductor device, characterized in that a resistor for connecting the upper two points is provided. In the microwave semiconductor device in which the matching circuits are arranged on the input side and the output side of the semiconductor element,
The matching circuit on the input side is:
Two or more transmission lines arranged in parallel are provided, and a signal input end and a signal output end of the two transmission lines are connected between two adjacent transmission lines among the two or more transmission lines. A microwave semiconductor device comprising a resistor.

Images