Differential circuit

Abstract

This differential circuit (10) multiplies an input differential signal by a differential signal of a local oscillation wave to convert the input differential signal to an output differential signal, the output differential signal being a differential signal of an intermediate frequency when the input differential signal is a differential signal of a high frequency and the output differential signal being a differential signal of a high frequency when the input differential signal is a differential signal of an intermediate frequency. The differential circuit is provided with two pairs of transistors (11, 12) and two pairs of signal lines that relay the differential signal of the local oscillation wave. One pair of signal lines (111, 112) of the two pairs of signal lines are connected to one pair of transistors (11) of the two pairs of transistors; the other pair of signal lines (121, 122) are connected to the other pair of transistors (12). The one pair of signal lines are disposed so as to intersect, while the other pair of signal lines are disposed so as not to intersect.　Due to this configuration, the present invention can provide a differential circuit that can reduce leakage of a local oscillation signal.

Description

Differential circuit

[0001] This invention relates to a differential circuit.

[0002] In wireless communication devices and high-frequency signal measuring devices, frequency converters are used to convert between high-frequency signals (RF signals) and intermediate-frequency signals (IF signals). Figures 8A and 8B show typical block diagrams of transmitters and receivers in wireless communication devices and high-frequency signal measuring devices, respectively. The data processing unit, which demodulates data in wireless communication devices and processes measurement data in high-frequency signal measuring devices, is composed of digital circuits. Since these digital circuits generally do not support the high frequencies of RF signals, frequency conversion between RF signals and IF signals is necessary. Frequency conversion is performed by a high-frequency circuit called a mixer. The mixer converts an RF signal to an IF signal or an IF signal to an RF signal by multiplying the local oscillator signal (LO signal) with the RF signal or IF signal.

[0003] Figures 9A and 9C show typical configurations of conventional mixers. Figures 9A and 9B show cascode mixers that perform frequency conversion (upconversion) from IF to RF using two transistors. In the configuration shown in Figure 9A, the IF signal input to a common-source field-effect transistor (FET) is modulated by the gate of a common-gate transistor located in the subsequent stage with a LO signal, and the IF signal and LO signal are multiplied to generate the RF signal. In the configuration shown in Figure 9B, the arrangement of IF and LO is reversed compared to the configuration in Figure 9A, and the IF signal and LO signal are multiplied to generate the RF signal. In these configurations, the transistors are set to a bias condition that causes amplification.

[0004] Fig. 9C shows the configuration of a resistive mixer (e.g., Non-Patent Document 1). In this configuration, an IF or RF signal input to the drain of a source-grounded transistor is modulated by an LO signal input to the gate and is converted to RF or IF, respectively. In a resistive mixer, since the transistor is biased to operate passively, both up-conversion and down-conversion are possible. The configurations shown in Figs. 9A to 9C use single-phase (single-ended) signals for all of IF, RF, and LO, and are called single-ended mixers.

[0005] However, in a single-ended mixer, as shown in Figs. 10A to 10C, a phenomenon occurs in which the LO signal leaks to the IF and RF ports (hereinafter referred to as "LO leak"; dotted arrows in the figures). The LO leak causes saturation of the subsequent IF and RF amplifiers (dotted arrow 51 in the figure) and unnecessary LO emission from the RF port (dotted arrow 52 in the figure) in each of the transmitter (Fig. 11A) and the receiver (Fig. 11B). Therefore, it is necessary to remove the LO leak in a single-ended mixer.

[0006] As a mixer having a function of removing LO leak, a differential mixer is known. Figs. 12A and 12B show the configurations of conventional differential mixers. Fig. 12A shows the configuration of a Gilbert cell mixer. In a Gilbert cell mixer, all of IF, LO, and RF are in a differential configuration. In this mixer, since the leak from LO to IF or RF is canceled, the LO leak can be suppressed. The Gilbert cell mixer is an up-conversion mixer, similar to the configurations shown in Figs. 9A and 9B, and can operate as a mixer having the same effect even when the LO port and the IF port are interchanged. Fig. 12B shows the configuration of a mixer (hereinafter referred to as "differential resistive mixer") in which the configuration of the resistive mixer shown in Fig. 9C is operated differentially. The differential resistive mixer can cancel the LO leak and can perform both up-conversion and down-conversion operations.

[0007] SA Maas, “A GaAs MESFET Mixer with Very Low Intermodulation,” IEEE Transactions on Microwave Theory and Techniques, vol. 35, no. 4, pp. 425-429, Apr. 1987.

[0008] As described above, differential resistive mixers can perform both up-conversion and down-conversion operations and can cancel out LO leaks. However, differential resistive mixers present problems in terms of layout on semiconductor integrated substrates. These will be explained in detail below with reference to Figure 13.

[0009] When a differential resistive mixer is laid out on a semiconductor integrated circuit board, the wiring of the LO port becomes asymmetrical, as shown in Figure 13, resulting in a configuration where the lengths of the LO+ side wiring and the LO- side wiring are different (dotted line area in the figure). Since the difference in wiring length due to this asymmetry is at most a few hundred μm, the difference in the amount of LO phase rotation due to the wiring length is small and does not pose a problem when the frequency band of the LO signal is not high.

[0010] However, this becomes a major problem when the frequency band of the LO signal exceeds 100 GHz. For example, in the case of a 300 GHz high-frequency circuit using an InP substrate, the phase of the LO rotates by 1° for every 1 μm of wiring length, so when the difference in wiring length is several hundred μm, the difference in the amount of LO phase rotation is several hundred degrees. In order to maintain the LO leak rejection function of the differential mixer, the phase difference between LO+ and LO- in Figure 13 must be kept exactly 180°. Therefore, this difference of several hundred degrees in the amount of phase rotation reduces the LO leak rejection function in the differential mixer. In particular, when the difference in the amount of phase rotation (the deviation of the phase difference from 180°) is 180°, the phases of the wiring on the positive phase signal side of the LO signal (LO+ signal) and the wiring on the negative phase signal side of the LO signal (LO- signal) become in phase, and the LO leak rejection function is completely lost.

[0011] To solve the problems described above, the differential circuit according to the present invention multiplies an input differential signal with the differential signal of a local oscillator wave to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising two pairs of transistors and two pairs of signal lines through which the differential signal of the local oscillator wave is transmitted, wherein one pair of signal lines of one pair of transistors is connected to one pair of transistors of the two pairs of transistors, and the other pair of signal lines is connected to the other pair of transistors, with one pair of signal lines of one pair crossing each other and the other pair of signal lines of the other pair not crossing each other.

[0012] Furthermore, the differential circuit according to the present invention multiplies an input differential signal with the differential signal of a local oscillator wave to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, and comprises a first transistor, a second transistor, a third transistor, a fourth transistor, an input positive-phase terminal into which the positive-phase signal of the input differential signal is input, an input negative-phase terminal into which the negative-phase signal of the input differential signal is input, an output positive-phase terminal into which the positive-phase signal of the output differential signal is output, and the negative-phase signal of the output differential signal The transistor comprises an output inverted phase terminal, a first terminal to which the positive phase signal of the differential signal of the local oscillator wave is input, and a second terminal to which the inverted phase signal of the differential signal of the local oscillator wave is input. It also comprises a first signal line connecting the first transistor and the second terminal, a fourth signal line connecting the fourth transistor and the second terminal, a second signal line connecting the second transistor and the first terminal, and a third signal line connecting the third transistor and the first terminal, wherein either the first signal line and the second signal line are arranged to cross each other, or the third signal line and the fourth signal line are arranged to cross each other.

[0013] According to the present invention, a differential circuit capable of reducing leakage of local oscillator signals can be provided.

[0014] Figure 1 is a schematic diagram showing the configuration of a differential circuit according to the first embodiment of the present invention. Figure 2 is a diagram for explaining the operation of the differential circuit according to the first embodiment of the present invention. Figure 3 is a diagram for explaining the operation of the differential circuit according to the first embodiment of the present invention. Figure 4 is a schematic diagram showing an example of the configuration of the phase inversion section in the differential circuit according to the first embodiment of the present invention. Figure 5A is a schematic diagram showing the configuration of a differential circuit according to the second embodiment of the present invention. Figure 5B is a schematic diagram showing an example of the configuration of a differential circuit according to the second embodiment of the present invention. Figure 5C is a schematic diagram showing an example of the configuration of a differential circuit according to the second embodiment of the present invention. Figure 6A is a diagram for explaining the effect of the differential circuit according to the second embodiment of the present invention. Figure 6B is a diagram for explaining the effect of the differential circuit according to the second embodiment of the present invention. Figure 7A is a diagram for explaining the effect of the differential circuit according to the second embodiment of the present invention. Figure 7B is a diagram for explaining the effect of the differential circuit according to the second embodiment of the present invention. Figure 8A is a block diagram showing an example of the configuration of a conventional transmitter having a mixer. Figure 8B is a block diagram showing an example of the configuration of a conventional receiver having a mixer. Figure 9A is a circuit diagram showing an example of the configuration of a conventional mixer. Figure 9B is a circuit diagram showing an example of a conventional mixer configuration. Figure 9C is a circuit diagram showing an example of a conventional mixer configuration. Figure 10A is a diagram illustrating the operation of a conventional mixer. Figure 10B is a diagram illustrating the operation of a conventional mixer. Figure 10C is a diagram illustrating the operation of a conventional mixer. Figure 11A is a diagram illustrating the operation of a conventional mixer. Figure 11B is a diagram illustrating the operation of a conventional mixer. Figure 12A is a circuit diagram showing an example of a conventional differential mixer configuration. Figure 12B is a circuit diagram showing an example of a conventional differential mixer configuration. Figure 13 is a diagram illustrating the operation of a conventional differential mixer.

[0015] <First Embodiment> A differential circuit according to the first embodiment of the present invention will be described with reference to Figures 1 to 4.

[0016] <Configuration of Differential Circuit> The differential circuit 10 according to this embodiment constitutes a differential mixer and multiplies the input differential signal of an intermediate frequency differential signal (hereinafter also referred to as the "IF signal") with the differential signal of a local oscillator wave (hereinafter also referred to as the "LO signal") to convert it into an output differential signal of a high frequency differential signal (hereinafter also referred to as the "HF signal").

[0017] The differential circuit 10 includes a first transistor Tr1, a second transistor Tr2, a third transistor Tr3, and a fourth transistor Tr4. It also includes an input positive phase terminal 131 to which the positive phase signal of the input differential signal (e.g., "IF+ signal") is input, an input negative phase terminal 132 to which the negative phase signal of the input differential signal (e.g., "IF- signal") is input, an output positive phase terminal 151 to which the positive phase signal of the output differential signal (e.g., "HF+ signal") is output, an output negative phase terminal 152 to which the negative phase signal of the output differential signal (e.g., "HF- signal") is output, an LO+ terminal (first terminal) 141 to which the positive phase signal of the differential signal of the local oscillator wave (hereinafter referred to as "LO+ signal") is input, and an LO- terminal (second terminal) 142 to which the negative phase signal of the differential signal of the local oscillator wave (hereinafter referred to as "LO- signal") is input.

[0018] The first transistor Tr1 comprises a first source, a first gate, and a first drain, with the first source being grounded.

[0019] The second transistor Tr2 comprises a second source, a second gate, and a second drain, with the second source being grounded.

[0020] The third transistor Tr3 comprises a third source, a third gate, and a third drain, with the third source being grounded.

[0021] The fourth transistor Tr4 comprises a fourth source, a fourth gate, and a fourth drain, with the fourth source being grounded.

[0022] In the differential circuit 10, the first transistor Tr1 and the second transistor Tr2 form a pair of transistors 11, and the third transistor Tr3 and the fourth transistor Tr4 form a pair of transistors 12. Thus, the differential circuit 10 comprises two pairs of transistors 11 and 12.

[0023] In the differential circuit 10, the first drain and the second drain are connected to the input positive phase terminal 131, respectively. The third drain and the fourth drain are connected to the input negative phase terminal 132, respectively.

[0024] Furthermore, the first drain and the third drain are connected to the output positive phase terminal 151, respectively. Also, the second drain and the fourth drain are connected to the output negative phase terminal 152, respectively.

[0025] Furthermore, the first gate is connected to the LO- terminal 142 via the signal line 111, the second gate is connected to the LO+ terminal 141 via the signal line 112, the third gate is connected to the LO+ terminal 141 via the signal line 121, and the fourth gate is connected to the LO- terminal 142 via the signal line 122.

[0026] In the differential circuit 10, a signal line 111 connecting the first gate to the LO- terminal (second terminal) 142 and a signal line 112 connecting the second gate to the LO+ terminal (first terminal) 141 are arranged to intersect. On the other hand, a signal line 121 connecting the third gate to the LO+ terminal (first terminal) 141 and a signal line 122 connecting the fourth gate to the (second terminal) 142 are arranged not to intersect. Here, the portion consisting of the intersecting part of signal lines 111 and 112 and the non-intersecting part of signal lines 121 and 122 is called the "phase inversion section" 16.

[0027] In the differential circuit 10, the first transistor Tr1 receives the positive phase signal of an intermediate frequency differential signal as an input differential signal via the input positive phase terminal 131 to the first drain, the negative phase signal of a local oscillator differential signal as an input differential signal, and outputs the positive phase signal of a high frequency differential signal as an output differential signal via the output positive phase terminal 151 from the first drain.

[0028] In the second transistor Tr2, the positive phase signal of the intermediate frequency differential signal is input to the second drain via the input positive phase terminal 131, the positive phase signal of the local oscillator differential signal is input to the second gate, and the negative phase signal of the high frequency differential signal is output from the second drain via the output negative phase terminal 152.

[0029] In the third transistor Tr3, the inverted phase signal of the intermediate frequency differential signal is input to the third drain via the input inverted phase terminal 132, the positive phase signal of the local oscillator differential signal is input to the third gate, and the positive phase signal of the high frequency differential signal is output from the third drain via the output positive phase terminal 151.

[0030] In the fourth transistor Tr4, the inverted phase signal of the intermediate frequency differential signal is input to the fourth drain via the input inverted phase terminal 132, the inverted phase signal of the local oscillator differential signal is input to the fourth gate, and the inverted phase signal of the high frequency differential signal is output from the fourth drain via the output inverted phase terminal 152.

[0031] Thus, in the differential circuit 10, one pair of signal lines that transmit the differential signal of the local oscillator wave input to the gate of one pair of transistors are arranged to cross each other, while the other pair of signal lines that transmit the differential signal of the local oscillator wave input to the gate of the other pair of transistors are arranged not to cross each other.

[0032] <Operation of Differential Circuit 10> The operation of the differential circuit 10 according to this embodiment will be explained with reference to Figures 2 and 3.

[0033] Figure 2 shows a diagram of the basic configuration that forms the basis of the differential circuit 10 according to this embodiment. In this configuration, two LO+ terminals 141_1 and 141_2 are connected to transistors Tr2 and Tr3, respectively, and two LO- terminals 142_1 and 142_2 are connected to transistors Tr1 and Tr4, respectively. LO+ terminal 141_1 and LO- terminal 142_1 form one terminal pair, and LO+ terminal 141_2 and LO- terminal 142_2 form the other terminal pair. Furthermore, the signal lines (LO+ signal lines) 1120 and 1210 that transmit the LO+ signal and the signal lines (LO- signal lines) 1110 and 1220 that transmit the LO- signal are wired to the same length.

[0034] Therefore, if a differential circuit with this configuration can be realized, the asymmetry of the differential mixer's circuit layout can be eliminated, and the phase difference between the LO+ signal and the LO- signal can be maintained at 180°. In order to realize a differential circuit with this configuration, it is necessary to consolidate the two LO+ terminals 141_1 and 141_2 and the two LO- terminals 141_1 and 141_2 into a single LO+ terminal and a single LO- terminal.

[0035] Therefore, as shown in Figure 3, in the differential circuit, the positions of the LO+ terminal 141_1 and the LO- terminal 142_1 are swapped in one terminal pair, and the LO+ signal line 1120 and the LO- signal line 1210 are crossed.

[0036] With respect to the configuration shown in Figure 3, a branching circuit can be used to consolidate the two LO+ terminals and two LO- terminals into a single LO+ terminal and a single LO- terminal, thereby forming the differential circuit 10 shown in Figure 1. This reduces the difference (path length difference) between the path length from the first terminal 141 of the LO+ signal to the output terminals (output positive phase terminal 151 and output negative phase terminal 152) via the gate terminals of the second and third transistors Tr2 and Tr3, and the path length from the second terminal 142 of the LO- signal to the output terminals (output positive phase terminal 151 and output negative phase terminal 152) via the gate terminals of the first and fourth transistors Tr4.

[0037] In detail, the phase inversion section 16 is formed by crossing adjacent differential signal lines, and can be formed by adding and arranging transmission lines with a maximum length of 50 μm or less. Therefore, the differential circuit 10 can be configured so that the above-mentioned path length difference is within 50 μm.

[0038] Thus, the configuration of the differential circuit 10 shown in Figure 1 can be realized by placing a branch circuit on the signal line (LO differential line) through which the LO differential signal shown in Figure 3 is transmitted.

[0039] In the differential circuit 10 according to this embodiment, the phase difference between the LO differential line (LO+ signal line and LO- signal line) at 300 GHz can be reduced from 180° to several hundred° in a conventional differential mixer (Figure 13), by about an order of magnitude to several tens of°.

[0040] In the differential circuit 10, by changing the shape of the non-crossing signal lines in the phase inversion section to reduce the difference between the length of the non-crossing signal lines and the length of the crossing signal lines, the phase difference between the LO differential lines can be further reduced. By making the difference between the length of the non-crossing signal lines and the length of the crossing signal lines equal, the phase difference between the LO differential lines can be made 180°.

[0041] For example, the non-crossing signal lines 121 and 122 in the phase inversion section may be bent or curved as shown in FIG. 4. Thereby, the difference between the lengths of the non-crossing signal lines 121 and 122 and the lengths of the crossing signal lines 111 and 112 can be made substantially equal. Here, substantially equal includes equal and includes the range of manufacturing error (for example, within 10 μm).

[0042] In the differential circuit 10, capacitance is generated in the crossing signal lines in the phase inversion section. To compensate for this capacitance, capacitance may be introduced into the non-crossing signal lines 121 and 122. For example, a capacitor may be connected between the non-crossing signal lines 121 and 122.

[0043] Also, to compensate for the capacitance generated in the crossing signal lines in the phase inversion section, capacitance may be introduced into the signal lines from the input inverting terminal 132 to the third and fourth transistors Tr3 and Tr4.

[0044] In the differential circuit 10, when the lengths of the signal lines from the input non-inverting terminal 131 to the first and second transistors Tr1 and Tr2 are different from the lengths of the signal lines from the input inverting terminal 132 to the third and fourth transistors Tr3 and Tr4, the phase difference between the output non-inverting signal and the output inverting signal deviates from 180°. Therefore, the signal lines from the input inverting terminal 132 to the third and fourth transistors Tr3 and Tr4 may be curved to be substantially equal to the length of the signal lines from the input non-inverting terminal 131. Thereby, the deviation of the phase difference between the output non-inverting signal and the output inverting signal from 180° can be reduced.

[0045] <Second Embodiment> The differential circuit according to the second embodiment of the present invention will be described with reference to FIGS. 5A to 7B.

[0046] <Configuration of Transceiver> The differential circuit 20 according to the present embodiment is a transmitter of a 300 GHz band transceiver. As shown in FIG. 5A, it includes an input balun 21, a power amplifier (PA) 22 for LO, a differential mixer (DBM) 23, an LLC 24, a PA 25 for RF, and an output balun 26.

[0047] The PA 22 for LO and the PA 25 for RF are each configured such that unit amplification stages each consisting of a five-stage differential amplifier are vertically connected in two stages as a design unit.

[0048] In the PA 22 for LO and the PA 25 for RF, in order to increase the output power, two unit amplification stages are arranged in parallel at the output part.

[0049] The differential mixer 23 is a differential resistive mixer similar to that in the first embodiment (FIG. 1). <00-00100> Similar to the first embodiment, the differential mixer 23 may include a phase inversion part. For example, alternatively, a phase inversion part may be directly connected to the LO port of the differential mixer.

[0051] Alternatively, the PA 22 for LO may include a phase inversion part 16. For example, as shown in FIG. 5A, in the PA 22 for LO having a two-stage amplification stage configuration, a phase inversion part 16 may be connected between each amplification stage. With this configuration, the loss generated in the phase inversion part can be compensated by the subsequent PA for LO.

[0052] Thus, in the differential circuit 20, the symmetry of the circuit layout of the entire transceiver can be maintained to remove LO leakage.

[0053] The transceiver in the differential circuit according to the present embodiment may include the receivers shown in FIGS. 5B and 5C.

[0054] The LO signal is input to the PA in the transmitter, thus saturating the PA. On the other hand, the LO signal is input to the output part of the low noise amplifier (LNA) in the receiver, so it does not saturate the LNA. Therefore, in the receiver, LO leakage is not as big a problem as in the transmitter.

[0055] Therefore, as shown in Figure 5B, the receiver includes an input balun 21_2, an RF differential amplifier 25_2, a differential mixer 23_2, an LO differential amplifier 22_2, and an output balun 26_2, and the LO differential amplifier 22_2 may be equipped with a phase inversion unit 16. In this configuration, LO leakage is not eliminated. The phase inversion unit 16 is not required.

[0056] Alternatively, as shown in Figure 5C, the receiver may include an input balun 21_3, an RF differential amplifier 25_3, an LLC 24_3, a differential mixer 23_3, an LO differential amplifier 22_3, and an output balun 26_3, with the LO differential amplifier 22_3 also being equipped with a phase inversion unit 16. In this configuration, LO leakage can be eliminated. This suppresses slight modulation of the bias of the LNA's output section due to LO leakage, which would otherwise change the LNA's gain.

[0057] Figures 6A and 6B show the configuration of the phase inversion section 16 in the transceiver transmitter of the differential circuit 20, and the calculation results of the phase difference in the phase inversion section 16. The calculations were performed using the software "ADS" (Keysight Technologies).

[0058] The phase inversion section 16 of the differential circuit 20 is composed of a cross line (Cross) 31 and a non-cross line (Bar) 32 of the differential line, similar to the first embodiment. As shown in Figure 6A, in the layout of Bar 32, the paths in Bar 32 and Cross 31 are made equal in length by arranging the signal lines in a curved or bent manner (by adding delay lines). In the figure, white arrows indicate the transmission of positive-phase signals, and black arrows indicate the transmission of negative-phase signals.

[0059] Figure 6B shows the phase rotation amount at Cross 31 (solid line in the figure) and the phase rotation amount at Bar 32 (dotted line in the figure) obtained by electromagnetic field analysis. The phase difference of the phase inversion section is 180° over a wide bandwidth.

[0060] In this way, by making the paths in the Cross and the Bar equal in length, the phase difference between the Bar and the Cross can be made 180°.

[0061] Figures 7A and 7B show the configuration used to calculate the LO leak in the differential circuit 20 and the calculation results of the LO leak.

[0062] As shown in Figure 7A, the LO input 41 of the unit mixer (dotted line in Figure 7B), the LO leak 42 of the unit mixer (dashed line in Figure 7B), and the LO leak 43 of the differential mixer (solid line in Figure 7B) were calculated. The intermediate frequency differential signal to be input was set to 27 GHz, -30 dBm, and the LO signal was set to 270 GHz.

[0063] When the LO input of a unit mixer is 4 dBm, the LO leak of each unit mixer constituting the differential mixer is approximately -15 dBm. On the other hand, the LO leak of the differential mixer is reduced to approximately -40 dBm.

[0064] As shown in Figure 5A, the circuit layout of the differential circuit 20 has high symmetry due to the use of a phase inversion section. This reduces LO leakage.

[0065] According to an embodiment of the present invention, the difference in the length of the signal paths through which the positive-phase signal (LO+ signal) and the negative-phase signal (LO- signal) of the differential signal of the local oscillator wave are transmitted can be reduced. As a result, the deviation of the phase difference between the LO+ signal and the LO- signal from 180° can be reduced. This reduces leakage (LO leakage) of the local oscillator signal.

[0066] In the embodiments of the present invention, as shown in Figure 1 and other figures, an example is shown in which the positive-phase and negative-phase signals of the intermediate frequency signal and the local oscillator signal are input to each of the first to fourth transistors, and the positive-phase and negative-phase signals of the high-frequency signal are output. However, the combination of positive-phase and negative-phase signals is not limited to this, and other combinations may also be used.

[0067] In the embodiments of the present invention, an example is shown in which the differential signal of the local oscillator is input to the gate of a transistor, but the invention is not limited to this. The differential signal of the local oscillator may be input to the source of the transistor or to the drain.

[0068] In the embodiments of the present invention, an example using a common-source transistor is shown, but the invention is not limited to this. A common-drain transistor or a common-gate transistor may also be used.

[0069] In the embodiments of the present invention, an example is shown in which the differential circuit is configured using a resistive mixer, but the invention is not limited to this. It may also be configured using a Gilbert cell mixer, or other mixers may be used.

[0070] In the embodiments of the present invention, an example is shown in which an intermediate frequency differential signal is input as the input differential signal and a high frequency differential signal is output as the output differential signal, but the invention is not limited to this. A high frequency differential signal may be input as the input differential signal and an intermediate frequency differential signal may be output as the output differential signal.

[0071] In the embodiments of the present invention, an example using an FET as the transistor is shown, but a bipolar transistor may also be used. When a bipolar transistor is used, the emitter, base, and collector of the bipolar transistor correspond to the source, gate, and drain of the FET, respectively.

[0072] In the embodiments of the present invention, examples of the structure, dimensions, materials, etc. of each component in the configuration and manufacturing method of the differential mixer and transceiver are shown, but the invention is not limited to these examples. Any configuration that allows the differential mixer and transceiver to perform their functions and achieve their desired effects is acceptable.

[0073] It should be noted that the present invention is not limited to the embodiments described above, and it is clear that many modifications and combinations can be implemented within the technical concept of the present invention by those with ordinary skill in the art.

[0074] Some or all of the embodiments described above, or examples thereof, may also be described as follows, but are not limited to these.

[0075] (Note 1) A differential circuit that multiplies an input differential signal by a differential signal of a local oscillator wave to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising two pairs of transistors and two pairs of signal lines through which the differential signal of the local oscillator wave is transmitted, wherein one pair of signal lines of one pair of transistors of the two pairs of transistors is connected to one pair of signal lines of the two pairs of signal lines, the other pair of signal lines of the other pair of transistors is connected to the other pair of transistors, the one pair of signal lines of one pair are arranged to cross each other, and the other pair of signal lines of the other pair are arranged not to cross each other.

[0076] (Note 2) The differential circuit described in Note 1, wherein the difference between the length of one pair of signal lines and the length of the other pair of signal lines is within 50 μm.

[0077] (Note 3) The differential circuit described in Note 1 or Note 2, wherein the other pair of signal lines is bent or curved, and the length of the one pair of signal lines is approximately equal to the length of the other pair of signal lines.

[0078] (Note 4) A differential circuit according to any one of Notes 1 to 3, wherein a capacitance is introduced to the other pair of signal lines to compensate for the capacitance generated in the one pair of signal lines.

[0079] (Note 5) A differential circuit according to any one of Notes 1 to 4, comprising: an input positive-phase signal line for transmitting the positive-phase signal of the input differential signal to one or the other pair of transistors; an input negative-phase signal line for transmitting the negative-phase signal of the input differential signal to the other or the one pair of transistors; an output positive-phase signal line for transmitting the positive-phase signal of the output differential signal from one or the other pair of transistors and one of the other or the one pair of transistors; and an output negative-phase signal line for transmitting the negative-phase signal of the output differential signal from one or the other pair of transistors and the other transistor of the other or the one pair of transistors.

[0080] (Note 6) The differential circuit described in Note 5, wherein either the input positive-sequence signal line or the input negative-sequence signal line is bent or curved, and the length of the input positive-sequence signal line and the length of the input negative-sequence signal line are approximately equal.

[0081] (Note 7) The differential circuit is a transmitter and comprises a first amplification circuit for amplifying the differential signal of the local oscillator wave, a differential mixer that receives the input differential signal and the amplified differential signal of the local oscillator wave and outputs the output differential signal, and a second amplification circuit for amplifying the output differential signal, wherein one pair of signal lines is arranged to cross over the first amplification circuit, as described in any of Notes 1 to 6.

[0082] (Note 8) A differential circuit that multiplies an input differential signal by a local oscillator differential signal to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising: a first transistor, a second transistor, a third transistor, a fourth transistor, an input positive-phase terminal into which the positive-phase signal of the input differential signal is input, an input negative-phase terminal into which the negative-phase signal of the input differential signal is input, an output positive-phase terminal into which the positive-phase signal of the output differential signal is output, and an output negative-phase terminal into which the negative-phase signal of the output differential signal is output. A differential circuit comprising a phase terminal, a first terminal into which the positive-phase signal of the differential signal of the local oscillator wave is input, and a second terminal into which the negative-phase signal of the differential signal of the local oscillator wave is input, a first signal line connecting the first transistor and the second terminal, a fourth signal line connecting the fourth transistor and the second terminal, a second signal line connecting the second transistor and the first terminal, and a third signal line connecting the third transistor and the first terminal, wherein either the first signal line and the second signal line are arranged to cross each other, or the third signal line and the fourth signal line are arranged to cross each other.

[0083] (Note 9) A differential circuit that multiplies an input differential signal by a local oscillator differential signal to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising a first transistor, a second transistor, a third transistor, and a fourth transistor, wherein the first transistor comprises a first source or emitter, a first gate or base, and a first drain or collector, and the first source Alternatively, the emitter is grounded, and the second transistor comprises a second source or emitter, a second gate or base, and a second drain or collector, and the second source or emitter is grounded, and the third transistor comprises a third source or emitter, a third gate or base, and a third drain or collector, and the third source or emitter is grounded, and the fourth transistor comprises a fourth source or emitter, a fourth gate or base, and a fourth drain or collector, and the fourth source or emitter is grounded The first transistor comprises a first signal line connected to the first gate or base, a second signal line connected to the second gate or base, a third signal line connected to the third gate or base, and a fourth signal line connected to the fourth gate or base, wherein the positive phase signal of the input differential signal is input to the first drain or collector, the negative phase signal of the differential signal of the local oscillator wave is input to the first gate or base, and the positive phase signal of the output differential signal is output from the first drain or collector, and the second transistor comprises a first signal line connected to the first gate or base, and the positive phase signal of the output differential signal is input to positive phase signal of the output differential signal is output from the first drain or collector, and Then, the positive-phase signal of the input differential signal is input to the second drain or collector, the positive-phase signal of the differential signal of the local oscillator is input to the second gate or base, and the negative-phase signal of the output differential signal is output from the second drain or collector; in the third transistor, the negative-phase signal of the input differential signal is input to the third drain or collector, the positive-phase signal of the differential signal of the local oscillator is input to the third gate or base, and the positive-phase signal of the output differential signal is output from the third drain or collector; in the fourth transistor,A differential circuit in which the inverse phase signal of the input differential signal is input to the fourth drain or collector, the inverse phase signal of the differential signal of the local oscillator wave is input to the fourth gate or base, the inverse phase signal of the output differential signal is output from the fourth drain or collector, and either the first signal line and the second signal line are arranged to intersect, or the third signal line and the fourth signal line are arranged to intersect.

[0084] (Note 10) A differential circuit that multiplies an input differential signal by the differential signal of a local oscillator wave to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising: a first transistor, a second transistor, a third transistor, a fourth transistor, an input positive-phase terminal, an input negative-phase terminal, an output positive-phase terminal, an output negative-phase terminal, a first terminal to which the positive-phase signal of the differential signal of the local oscillator wave is input, and the local oscillator The first transistor comprises a first source or emitter, a first gate or base, and a first drain or collector, with the first source or emitter being grounded. The second transistor comprises a second source or emitter, a second gate or base, and a second drain or collector, with the second source or emitter being grounded. The third transistor comprises a third source or emitter, a third gate or base, and a third drain or collector, and the The source or emitter of transistor 3 is grounded, and the fourth transistor comprises a fourth source or emitter, a fourth gate or base, and a fourth drain or collector, the fourth source or emitter is grounded, the first drain or collector and the second drain or collector each have signal lines connected to the input positive phase terminal, the third drain or collector and the fourth drain or collector each have signal lines connected to the input negative phase terminal, and the first gate or base and the fourth gate or base each have connections to the second terminal The device comprises a connecting signal line, a signal line connecting the second gate or base and the third gate or base to the first terminal, a signal line connecting the first drain or collector and the third drain or collector to the output positive phase terminal, and a signal line connecting the second drain or collector and the fourth drain or collector to the output negative phase terminal, wherein the signal line connecting the first gate or base and the second terminal and the signal line connecting the second gate or base and the first terminal are arranged to intersect.A differential circuit in which either the signal line connecting the third gate or base and the first terminal and the signal line connecting the fourth gate or base and the second terminal are arranged to intersect.

[0085] This invention relates to a differential circuit and can be applied to mixers, transceivers, wireless communication devices, and high-frequency signal measuring devices.

[0086] 10 Differential circuit 11 One pair of transistors 12 The other pair of transistors 111, 112 One pair of signal lines 121, 122 The other pair of signal lines

Claims

1. A differential circuit that multiplies an input differential signal by a differential signal of a local oscillator wave to convert it into an output differential signal, wherein when the input differential signal is a high-frequency differential signal, the output differential signal is an intermediate-frequency differential signal, and when the input differential signal is an intermediate-frequency differential signal, the output differential signal is a high-frequency differential signal, comprising two pairs of transistors and two pairs of signal lines through which the differential signal of the local oscillator wave is transmitted, wherein one pair of signal lines of one pair of transistors of the two pairs of transistors is connected to one pair of signal lines of the two pairs of signal lines, the other pair of signal lines of the other pair of transistors is connected to the other pair of transistors, the one pair of signal lines of one pair are arranged to cross each other, and the other pair of signal lines are arranged not to cross each other.

2. The differential circuit according to claim 1, wherein the difference between the length of one pair of signal lines and the length of the other pair of signal lines is within 50 μm.

3. The differential circuit according to claim 1 or claim 2, wherein the other pair of signal lines is bent or curved, and the length of the one pair of signal lines and the length of the other pair of signal lines are substantially equal.

4. The differential circuit according to claim 1 or claim 2, wherein a capacitance is introduced to the other pair of signal lines to compensate for the capacitance generated in the one pair of signal lines.

5. A differential circuit according to claim 1 or 2, comprising: an input positive-phase signal line for transmitting the positive-phase signal of the input differential signal to one or the other pair of transistors; an input negative-phase signal line for transmitting the negative-phase signal of the input differential signal to the other or the one pair of transistors; an output positive-phase signal line for transmitting the positive-phase signal of the output differential signal from one or the other pair of transistors and one of the other or the one pair of transistors; and an output negative-phase signal line for transmitting the negative-phase signal of the output differential signal from one or the other pair of transistors and the other transistor of the other or the one pair of transistors.

6. The differential circuit according to claim 5, wherein either the input positive-phase signal line or the input negative-phase signal line is bent or curved, and the length of the input positive-phase signal line and the length of the input negative-phase signal line are substantially equal.

7. The differential circuit according to claim 1 or 2, wherein the differential circuit is a transmitter comprising: a first amplification circuit for amplifying the differential signal of the local oscillator wave; a differential mixer that receives the input differential signal and the amplified differential signal of the local oscillator wave and outputs the output differential signal; and a second amplification circuit for amplifying the output differential signal, wherein one pair of signal lines is arranged to cross over the first amplification circuit.

8. A differential mixer that multiplies an input differential signal of a high-frequency differential signal or an intermediate-frequency differential signal with a differential signal of a local oscillator wave and converts it into an output differential signal of an intermediate-frequency differential signal or a high-frequency differential signal, comprising: a first transistor; a second transistor; a third transistor; a fourth transistor; an input positive-phase terminal into which the positive-phase signal of the input differential signal is input; an input negative-phase terminal into which the negative-phase signal of the input differential signal is input; an output positive-phase terminal into which the positive-phase signal of the output differential signal is output; an output negative-phase terminal into which the negative-phase signal of the output differential signal is output; a first terminal into which the positive-phase signal of the differential signal of the local oscillator wave is input; and a second terminal into which the negative-phase signal of the differential signal of the local oscillator wave is input. A differential circuit comprising: a first signal line connecting the first transistor and the second terminal; a fourth signal line connecting the fourth transistor and the second terminal; a second signal line connecting the second transistor and the first terminal; and a third signal line connecting the third transistor and the first terminal, wherein either the first signal line and the second signal line are arranged to cross each other, or the third signal line and the fourth signal line are arranged to cross each other.

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