Millimeter wave phase shifter and phased array system

Abstract

The invention relates to the technical field of communication, and discloses a millimeter wave phase shifter and a phased array system with the same, and the phase shifter comprises an input matching network, an orthogonal generator, an I-path phase shift circuit, a Q-path phase shift circuit and an output matching network. The input end of the input matching network is connected with the input bonding pad, the orthogonal generator is of an inductance compensation type transformer structure, the second end of the primary inductor of the first transformer and the second end of the primary inductor of the second transformer are both connected with first inductors in series, and a first resistor is connected between the two first inductors. Each of the I-path phase-shifting circuit and the Q-path phase-shifting circuit comprises a matching network, an amplifier and a DAC switch array which are connected in sequence; and the output ends of the amplifiers in the I-path phase-shifting circuit and the Q-path phase-shifting circuit are connected with a second inductor in parallel. The input end of the output matching network is connected with the output ends of the I-path phase-shifting circuit and the Q-path phase-shifting circuit, and the output end of the output matching network is connected with the output bonding pad. The phase shifter is relatively small in physical size and relatively high in bandwidth.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a millimeter wave phase shifter and a phased array system using the millimeter wave phase shifter. Background Art

[0002] The phased array system can perform spatial superposition in a specific direction, thereby effectively increasing the transmission distance and improving the signal-to-noise ratio. It also has functions such as beam forming and beam scanning, and is one of the core technologies in communication and radar systems. The phase shifter is one of the core components of the phased array system, and its phase shifting accuracy determines the spatial superposition effect of the phased array system. Phase shifters are mainly divided into passive phase shifters and active phase shifters. The orthogonal generators of existing active phase shifters mostly use a Lange coupler structure, and their length is usually one-quarter of the wavelength corresponding to the operating frequency, resulting in a larger overall chip area. And with the improvement of phase shifting accuracy, the number of switches used in the vector synthesis switch array increases, which will limit the bandwidth of the phase shifter. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a millimeter wave phase shifter that can reduce the chip area while ensuring the phase shifting performance and can widen the overall bandwidth.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: a millimeter wave phase shifter, comprising: an input matching network, the input end of which is connected to the input pad, for converting an input single-ended signal into a differential signal; an orthogonal generator, comprising two transformers, wherein the first end of the secondary inductor of the first transformer is connected to the positive electrode of the output end of the input matching network, the first end of the secondary inductor of the second transformer is connected to the negative electrode of the output end of the input matching network, the second end of the primary inductor of the first transformer and the second end of the primary inductor of the second transformer are both connected in series with a first inductor, and a first resistor is connected between the two first inductors; an I-path phase shift circuit and a Q-path phase shift circuit. The circuits each include a matching network, an amplifier and a DAC switch array connected in sequence, the output ends of the amplifiers in the I-path phase shift circuit and the Q-path phase shift circuit are both connected in parallel with a second inductor, the positive and negative poles of the input end of the I-path phase shift circuit are respectively connected to the second ends of the secondary inductors of the first transformer and the second transformer, and the positive and negative poles of the input end of the Q-path phase shift circuit are respectively connected to the first ends of the primary inductors of the first transformer and the second transformer; an output matching network, the input end of which is connected to the output end of the I-path phase shift circuit and the Q-path phase shift circuit, and the output end is connected to an output pad, for converting a differential signal into a single-ended signal for output.

[0005] Compared with the prior art, the beneficial effects of the present invention are: the orthogonal generator with an inductor compensation transformer structure improves the phase shift performance while having a smaller physical size and can reduce the chip area. And because there is no independent capacitor element, the influence of the deviation caused by the processing error on the phase shift accuracy can be effectively reduced. By connecting the inductor in parallel to the output end of the amplifier, the inductor resonates with the parasitic capacitance in the DAC switch array, thereby improving the overall bandwidth. The overall circuit adopts a differential structure, which can effectively reduce the influence of even harmonics on the circuit.

[0006] In the above-mentioned millimeter wave phase shifter, the body end of each switch tube in the DAC switch array is grounded through a second resistor.

[0007] In the above-mentioned millimeter wave phase shifter, the resistance of the first resistor is 100 ohms.

[0008] In the above-mentioned millimeter wave phase shifter, the resistance of the second resistor is 5000 ohms.

[0009] The above-mentioned millimeter-wave phase shifter, the amplifier includes two transistors of the same size, the sources of the first transistor and the second transistor are both grounded, the gates of the first transistor and the second transistor are respectively connected to the positive and negative electrodes of the output end of the corresponding matching network, the drains of the first transistor and the second transistor are respectively connected to the positive and negative electrodes of the output end of the corresponding DAC switch array, and a neutralizing capacitor is connected between the gate of the first transistor and the drain of the second transistor, and between the gate of the second transistor and the drain of the first transistor.

[0010] In the above-mentioned millimeter wave phase shifter, the DAC switch arrays in the I-path phase shift circuit and the Q-path phase shift circuit both adopt a complementary switch structure.

[0011] In the above-mentioned millimeter wave phase shifter, the DAC switch array includes a plurality of switch units connected in parallel, each of the switch units includes four switch tubes of the same size, the sizes of the switch tubes in the plurality of switch units are multiplied step by step, the source of the first switch tube and the source of the second switch tube in the switch unit are both connected to the positive electrode of the output end of the corresponding amplifier, the source of the third switch tube and the fourth switch tube in the switch unit are both connected to the negative electrode of the output end of the corresponding amplifier, the drain of the first switch tube and the third switch tube are both connected to the positive electrode of the input end of the output matching network, the drain of the second switch tube and the fourth switch tube are both connected to the negative electrode of the output end of the output matching network, the gates of the first switch tube to the fourth switch tube are both connected to the output end of the corresponding decoder, and the control signal of the gate input of the first switch tube and the fourth switch tube is opposite to the control signal of the gate input of the second switch tube and the third switch tube.

[0012] A phased array system, characterized by comprising the above-mentioned millimeter wave phase shifter.

[0013] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a principle block diagram of a millimeter wave phase shifter according to an embodiment of the present invention;

[0015] Figure 2 is a schematic diagram of an orthogonal generator according to an embodiment of the present invention;

[0016] Figure 3 is a schematic diagram of an amplifier according to an embodiment of the present invention;

[0017] Figure 4 is a schematic diagram of a DAC switch array according to an embodiment of the present invention;

[0018] Figure 5 is a schematic diagram of a switch tube in a DAC switch array according to an embodiment of the present invention;

[0019] Figure 6 The S21 simulation result diagram of the phase shifter with and without the parallel resistor is shown;

[0020] Figure 7 The S21 simulation result diagram of the phase shifter with body-terminated high resistance and body-terminated source end;

[0021] Figure 8 This is a diagram showing the simulation results of the input end reflection coefficient of the millimeter wave phase shifter according to an embodiment of the present invention;

[0022] Fig. 9 This is a diagram showing the simulation results of the output end reflection coefficient of the millimeter wave phase shifter according to an embodiment of the present invention;

[0023] Fig.10 Insertion loss simulation result diagram of the millimeter wave phase shifter according to an embodiment of the present invention;

[0024] Fig.11 This is a diagram of S21 simulation results of the millimeter wave phase shifter according to an embodiment of the present invention;

[0025] Fig.12 Graph showing RMS simulation results of the millimeter wave phase shifter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below. Figure 1 and Figure 2, an embodiment of the present invention provides a millimeter wave phase shifter, including an input matching network, an orthogonal generator, an I-way phase shift circuit, a Q-way phase shift circuit and an output matching network. The input end of the input matching network is connected to the input pad, and is used to convert the input single-ended signal into a differential signal. The orthogonal generator includes two transformers, wherein the first end of the secondary inductor Ls of the first transformer is connected to the positive pole of the output end of the input matching network, and the first end of the secondary inductor Ls of the second transformer is connected to the negative pole of the output end of the input matching network. The second ends of the primary inductors Lp of the first transformer and the second transformer serve as isolation ends, and are both connected in series with a first inductor Le, and a first resistor is connected between the two first inductors Le. The second ends of the secondary inductors Ls of the first transformer and the second transformer serve as through ends, and are connected to the input end of the I-way phase shift circuit. The first ends of the primary inductors Lp of the first transformer and the second transformer serve as coupling ends, and are connected to the input end of the Q-way phase shift circuit. The I-way phase shift circuit and the Q-way phase shift circuit both include a matching network, an amplifier and a DAC switch array connected in sequence, wherein the output end of the amplifier is connected in parallel with a second inductor. The input end of the output matching network is connected to the output end of the I phase shift circuit and the Q phase shift circuit, and the output end is connected to the output pad, so as to reconvert the differential signals output by the two phase shift circuits into single-ended signals for output.

[0027] The millimeter wave phase shifter of the embodiment of the present invention uses an inductor compensation transformer structure as an orthogonal generator. By adjusting the primary inductance Lp, secondary inductance Ls and coupling coefficient K of the transformer, as well as the value of the first inductance Le as the compensation inductor, the input signal can be converted into two differential signals with equal amplitude and a phase difference of 90 degrees within the required frequency band, and input into the I-path phase shift circuit and the Q-path phase shift circuit through the through-end and the coupling end respectively. Compared with the Lange coupler, the orthogonal generator has a smaller physical size, which can greatly reduce the chip area, and since there is no independent capacitor element, the deviation caused by processing errors can be effectively reduced. At the same time, due to the compensation inductance, the performance of the overall circuit can be improved. Reference Figure 6 As shown, the millimeter wave phase shifter also connects an inductor in parallel to the output end of the amplifier, so that the incorporated second inductor resonates with the parasitic capacitance in the DAC switch array, which can increase the 3dB bandwidth of the phase shifter from the original 7.6Ghz to 11.4GHz under the same conditions, and increase the overall bandwidth by 50%. The millimeter wave phase shifter of the embodiment of the present invention can effectively reduce the influence of even harmonics on the circuit by adopting a differential structure.

[0028] In this embodiment, the phase shifter needs to operate in the 60 GHz band. First, the primary inductance Lp, the secondary inductance Ls and the coupling coefficient K are reasonably designed so that the orthogonal generator operates in a frequency band near 60 GHz. Then, the value of the first inductance Le is adjusted so that the orthogonal generator can generate two equal-amplitude orthogonal output signals within the required operating frequency range.

[0029] Reference Figure 3 In this embodiment, the amplifier adopts a common source amplifier structure, including two transistors of the same size, the gates of the two transistors are used as the positive and negative electrodes of the differential input, respectively connected to the positive and negative electrodes of the through terminal or the coupling terminal of the orthogonal generator, the source electrodes are grounded, and the drain electrodes are used as the output terminals to be connected to the input terminals of the corresponding DAC switch array. A neutralizing capacitor C is connected between the gate of the first transistor and the drain of the second transistor, and between the gate of the second transistor and the drain of the first transistor. N , to increase the gain of the transistor and improve its stability.

[0030] Reference Figure 4 In this embodiment, the DAC switch array adopts a complementary switch structure, which helps to stabilize its impedance and facilitates the design of the matching circuit. Specifically, the DAC switch array includes a plurality of switch units connected in parallel. The number of switch units needs to be determined according to the number of bits of the decoder. In this embodiment, it is a 6-phase shifter, so there are 6 switch units. Each switch unit includes four switch tubes of the same size. The sizes of the switch tubes in the plurality of switch units are multiplied step by step. In this embodiment, the size ratio of the switch tubes in the first to sixth switch units is 1:2:4:8:16:32. The source electrodes of the first and second switch tubes in the switch unit are connected to the positive electrode of the output end of the corresponding amplifier, the source electrodes of the third and fourth switch tubes are connected to the negative electrode of the output end of the corresponding amplifier, the drain electrodes of the first and third switch tubes are connected to the positive electrode of the input end of the output matching network, and the drain electrodes of the second and fourth switch tubes are connected to the negative electrode of the output end of the output matching network. The gates of the first to fourth switch tubes are all connected to the output terminals of the corresponding decoders, and the control signals input to the gates of the first and fourth switch tubes are opposite to the control signals input to the gates of the second and third switch tubes. If the gates of the first and fourth switch tubes in the DAC switch array of I-way are input with high-level signals, the gates of the second and third switch tubes are input with low-level signals, and vice versa.

[0031] Reference Figure 5In order to improve the insertion loss of the phase shifter, in this embodiment, the body end of each switch tube in the DAC switch array is grounded through a second resistor with a higher resistance value to improve the gain loss of the switch tube. In this embodiment, the resistance value of the first resistor is 100 ohms and the resistance value of the second resistor is 5000 ohms. The S21 simulation results with and without high resistance at the body end under the same conditions are shown in Figure 1. Figure 7 As shown by Figure 7 It can be seen that connecting the body end to high resistance can effectively improve the gain loss.

[0032] Reference Figures 8 to 12 As can be seen from the figure, the millimeter-wave phase shifter of the embodiment of the present invention has good input and output matching in the range of 53-68GHz. In different phase shifting states, in the range of 53-68GHz, the RMS phase error and gain error of the phase shifter are less than 3 degrees and 0.7dB respectively, and the performance of the phase shifter is good.

[0033] The phased array system of the embodiment of the present invention includes the above-mentioned millimeter wave phase shifter. Since the millimeter wave phase shifter is smaller in size and has good performance, the phased array system of the embodiment of the present invention can have a higher degree of integration and a better spatial superposition effect.

[0034] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0035] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A millimeter wave phase shifter, characterized in that: include: An input matching network, the input end of which is connected to the input pad, and is used to convert an input single-ended signal into a differential signal; The orthogonal generator comprises two transformers, wherein the first end of the secondary inductor of the first transformer is connected to the positive electrode of the output end of the input matching network, the first end of the secondary inductor of the second transformer is connected to the negative electrode of the output end of the input matching network, the second end of the primary inductor of the first transformer and the second end of the primary inductor of the second transformer are both connected in series with a first inductor, and a first resistor is connected between the two first inductors; The I-path phase shift circuit and the Q-path phase shift circuit each include a matching network, an amplifier, and a DAC switch array connected in sequence, the output ends of the amplifiers in the I-path phase shift circuit and the Q-path phase shift circuit are both connected in parallel with a second inductor, the positive electrode and the negative electrode of the input end of the I-path phase shift circuit are respectively connected to the second ends of the secondary inductors of the first transformer and the second transformer, and the positive electrode and the negative electrode of the input end of the Q-path phase shift circuit are respectively connected to the first ends of the primary inductors of the first transformer and the second transformer; The output matching network has an input end connected to the output ends of the I-path phase shift circuit and the Q-path phase shift circuit, and an output end connected to the output pad, and is used for converting the differential signal into a single-ended signal for output.

2. The millimeter wave phase shifter according to claim 1, characterized in that: The body end of each switch tube in the DAC switch array is grounded through a second resistor.

3. The millimeter wave phase shifter according to claim 1, characterized in that: The resistance of the first resistor is 100 ohms.

4. The millimeter wave phase shifter according to claim 2, characterized in that: The resistance of the second resistor is 5000 ohms.

5. The millimeter wave phase shifter according to claim 1, characterized in that: The amplifier includes two transistors of the same size, the sources of the first transistor and the second transistor are both grounded, the gates of the first transistor and the second transistor are respectively connected to the positive and negative electrodes of the output ends of the corresponding matching networks, the drains of the first transistor and the second transistor are respectively connected to the positive and negative electrodes of the output ends of the corresponding DAC switch arrays, and a neutralizing capacitor is connected between the gate of the first transistor and the drain of the second transistor, and between the gate of the second transistor and the drain of the first transistor.

6. The millimeter wave phase shifter according to claim 1, characterized in that: The DAC switch arrays in the I-path phase shift circuit and the Q-path phase shift circuit both adopt a complementary switch structure.

7. The millimeter wave phase shifter according to claim 6, characterized in that: The DAC switch array includes a plurality of switch units connected in parallel, each of the switch units includes four switch tubes of the same size, the sizes of the switch tubes in the plurality of switch units are multiplied step by step, the source of the first switch tube and the source of the second switch tube in the switch unit are both connected to the positive electrode of the output end of the corresponding amplifier, the source of the third switch tube and the fourth switch tube in the switch unit are both connected to the negative electrode of the output end of the corresponding amplifier, the drain of the first switch tube and the third switch tube are both connected to the positive electrode of the input end of the output matching network, the drain of the second switch tube and the fourth switch tube are both connected to the negative electrode of the output end of the output matching network, the gates of the first switch tube to the fourth switch tube are both connected to the output end of the corresponding decoder, and the control signal of the gate input of the first switch tube and the fourth switch tube is opposite to the control signal of the gate input of the second switch tube and the third switch tube.

8. A phased array system, characterized in that: Comprising the millimeter wave phase shifter according to any one of claims 1 to 7.

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