TSV-based dual-band power splitter balun

Abstract

The present invention discloses a dual-band power divider balun based on TSVs. The balun comprises an upper RDL silicon dioxide isolation layer, a silicon substrate, and a lower RDL silicon dioxide isolation layer, arranged sequentially from top to bottom. An RDL coupler is disposed within the lower RDL silicon dioxide isolation layer. The RDL coupler connects two symmetrically arranged power divider input capacitors via TSVs connecting the power divider output and the coupler input. Each power divider input capacitor is connected in parallel to a set of TSV mutual inductors and a power divider GND connection capacitor. The mutual inductors and the power divider input capacitors are both connected to the input signal tap. This power divider balun structure reduces the balun area and achieves higher integration under dual-band operating conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of passive devices and relates to a dual-band power divider balun based on TSV. Background Art

[0002] The ultra-high-speed development of wireless communications has put forward requirements for RF passive components such as the ability to operate in multiple frequency bands, high balance, and small footprint.

[0003] Baluns are widely used in differential circuit designs, such as power amplifiers, balanced mixers, and antenna feed networks. As a key component in providing differential signals, baluns convert unbalanced single-ended signals into two balanced signal components with equal amplitude and a 180° phase difference. Baluns are generally categorized as active or passive. Passive baluns offer advantages such as high phase balance, amplitude balance, compact size, and wide bandwidth, and can be implemented in a variety of ways.

[0004] As a key component of three-dimensional integrated circuits, TSV technology offers advantages such as high density, high-speed transmission, and stability. It is widely used in fields such as three-dimensional integrated circuits and MEMS systems to enable information exchange and transmission between different layers. In planar integrated circuits, metal wires connect chips to each other, while vertical interconnects allow for stacking of all different chips and systems. TSV-based dual-band power divider baluns provide efficient signal conversion and transmission across multiple frequency bands, significantly improving transmission efficiency, reducing power consumption, and saving costs. This frees the balun design from the constraints of a two-dimensional plane, allowing for greater freedom and ensuring excellent reliability in terms of mechanical strength, thermal stress, and heat dissipation. Summary of the Invention

[0005] The object of the present invention is to provide a dual-band power divider balun based on TSV, wherein the power divider balun structure reduces the balun area under dual-band working conditions and has a higher integration level.

[0006] The technical solution adopted by the present invention is that a dual-band power divider balun based on TSV includes an upper RDL silicon dioxide isolation layer, a silicon substrate and a lower RDL silicon dioxide isolation layer arranged in sequence from top to bottom. An RDL coupler is arranged in the lower RDL silicon dioxide isolation layer. The RDL coupler connects two symmetrically arranged power divider input capacitors through a TSV connecting the power divider output and the coupler input. Each power divider input capacitor is respectively connected in parallel to a group of TSV mutual inductors and a power divider GND connection capacitor. The mutual inductor L m The input capacitors of the power divider are connected to the input signal taps.

[0007] The present invention is also characterized in that:

[0008] Each set of TSV mutual inductors includes two spiral TSV inductors connected in series. The two TSV inductors are connected in series with the power divider GND connected capacitor in parallel. The power divider GND connected capacitor is connected to the GND located in the upper RDL silicon dioxide isolation layer. The GND located in the upper RDL silicon dioxide isolation layer is connected to the GND located in the lower RDL silicon dioxide isolation layer through the TSV connecting the upper and lower GNDs.

[0009] The upper plates of the two power divider input capacitors are connected to the input signal tap, the lower plates of the two power divider input capacitors are connected to the power divider isolation resistor, and the lower plates of the two power divider input capacitors are connected to the RDL coupler through the TSV connecting the power divider output and the coupler input.

[0010] The RDL coupler includes a coupler input signal layer of the bottom RDL and a coupler output signal layer of the bottom RDL that are coupled to each other. The coupler input signal layer of the bottom RDL is connected to the TSV of the coupler input, and the coupler output signal layer of the bottom RDL is respectively connected to the short-circuit output signal end and the open-circuit output signal end.

[0011] The method for realizing dual-band by using a dual-band power splitter balun based on TSV includes the following steps:

[0012] The input signal is divided into two paths by the input signal tap input and enters two symmetrically set power divider input capacitors, and is transmitted to the power divider isolation resistor through the power divider input capacitor, and the output isolation is achieved through the power divider isolation resistor; the isolated signal at both ends of the power divider isolation resistor is transmitted to the RDL coupler through the TSV connecting the power divider output and the coupler input, and first passes through the coupler input signal layer of the bottom RDL to generate a wide-side coupled signal to reach the coupler output signal layer of the bottom RDL, and the generated output coupled signal is output by the short-circuit output signal end and the open-circuit output signal end. The short-circuit output signal end is respectively connected to the GND located in the upper RDL silicon dioxide isolation layer and the GND located in the lower RDL silicon dioxide isolation layer to form a short circuit, providing a -90° phase difference of the balun, and the open-circuit output signal end is left open to provide a +90° phase difference of the balun, thereby realizing a dual-band balun with an output phase difference of 180°.

[0013] The beneficial effect of the present invention is that the present invention is a dual-band power divider balun based on TSV. This structure can effectively reduce the volume of the balun, and use a 3dB coupler to generate two 90° phase offsets respectively in the working state of the dual-band power divider, while improving the phase and amplitude balance of the balun. By utilizing the excellent electrical characteristics of TSV technology, the signal transmission path is shortened, and the upper and lower layer output ports are flexibly set. Compared with ordinary baluns, it can work in dual bands at the same time. After being implemented using TSV, the balun has better symmetry and balance, good out-of-band suppression characteristics, compact structure, simple design, and strong thermal stability and low temperature drift characteristics. At the same time, it can use the RDL on the substrate to interconnect with other circuits, improve three-dimensional integrated packaging and be widely used in various radio frequency circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the schematic diagram of the dual-band power divider balun;

[0015] Figure 2 yes Figure 1 Circuit diagram of the power divider part;

[0016] Figure 3 It is a schematic structural diagram of a dual-band power splitter balun based on TSV of the present invention;

[0017] Figure 4 It is a structural diagram of the connection between the TSVs connecting the upper and lower GNDs and the TSVs connecting the power divider output and the coupler input and the RDL coupler in the TSV-based dual-band power divider balun of the present invention;

[0018] Figure 5 It is a schematic structural diagram of the RDL coupler in the TSV-based dual-band power splitter balun of the present invention;

[0019] Figure 6 Schematic diagram of the structure of the spiral TSV in the TSV-based dual-band power divider balun of the present invention;

[0020] Figure 7 This is a schematic diagram of the connection structure between the TSV copper pillar and the silicon substrate in the TSV-based dual-band power divider balun of the present invention;

[0021] Figure 8 It is a schematic structural diagram of the TSV copper pillar in the TSV-based dual-band power divider balun of the present invention;

[0022] Figure 9 This is a schematic structural diagram of the connection between the power divider GND connection capacitor and the silicon nitride dielectric layer of the power divider capacitor in the TSV-based dual-band power divider balun of the present invention;

[0023] Figure 10This is an S-parameter simulation diagram of the TSV-based dual-band power splitter balun of the present invention;

[0024] Figure 11 This is a phase diagram of the TSV-based dual-band power divider balun of the present invention.

[0025] In the figure, 1. Inductor RDL, 2. Power divider input capacitor, 3. Input signal tap, 4. GND, 5. Coupler input signal layer of the bottom RDL, 6. TSV isolation layer, 7. Coupler output signal layer of the bottom RDL, 8. Power divider GND connection capacitor, 9. TSV copper pillar, 10. Silicon substrate, 11. Lower RDL silicon dioxide isolation layer, 12. Short-circuit output signal terminal, 13. Open-circuit output signal terminal, 14. TSV connecting upper and lower GNDs, 15. TSV connecting power divider output and coupler input, 16. Power divider isolation resistor, 17. Power divider capacitor dielectric layer silicon nitride, 18. Upper RDL silicon dioxide isolation layer. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The present invention is based on the dual-band power divider balun of TSV, and the principle diagram of the power divider balun is as follows: Figure 1 As shown in the figure, the balun adopts the design of dual-band branch line balun. The balun provides amplitude balance at the output end with a three-port Wilkins power divider (power divider part). The resistor connected after the power divider provides port signal isolation. The +90° and -90° phase shifts can be formed by using two 3dB branch couplers (coupler part) with open circuit and short circuit at the path and isolation ports respectively. In order to achieve the dual-band working range, the dual-band λ / 4 wavelength transmission line circuit of the power divider part is as follows Figure 2 The bridged T-coil (BTC) composed of two series inductors Ls (the two inductors Ls form a coupled mutual inductance Lm), a parallel capacitor Cp and a bridge capacitor Cs is equivalent to two transmission lines of different frequencies. An isolation resistor R is added at the end of the power divider to improve the isolation performance of the output port of the balun. The end output of the power divider is connected to two 3dB branch couplers respectively.

[0028] Example 1

[0029] The present invention is based on the dual-band power divider balun of TSV, the structure is as follows Figure 3 As shown, the upper RDL silicon dioxide isolation layer 18, the silicon substrate 10 and the lower RDL silicon dioxide isolation layer 11 are sequentially arranged from top to bottom, the input signal tap 3 is arranged in the upper RDL silicon dioxide isolation layer 18, and the input signal tap 3 is respectively connected to two symmetrically arranged power divider input capacitors 2 (corresponding to Figure 2The upper plates of the two power divider input capacitors 2 are connected to the input signal tap 3, and the lower plates of the two power divider input capacitors 2 are connected to the power divider isolation resistor 16, as shown in FIG. Figure 4 As shown, the lower plates of the two power divider input capacitors 2 are connected to the coupler input signal layer 5 of the bottom RDL through the TSV 15 connecting the power divider output and the coupler input, and the TSV 15 connecting the power divider output and the coupler input is located in the silicon substrate 10. The coupler input signal layer 5 of the bottom RDL is coupled with the coupler output signal layer 7 of the bottom RDL, and together they constitute an RDL coupler (equivalent to Figure 2 The power divider part in the bottom RDL), the coupler input signal layer 5 of the bottom RDL and the coupler output signal layer 7 of the bottom RDL are both arranged in the lower RDL silicon dioxide isolation layer 11, as shown Figure 5 As shown, the coupler output signal layer 7 of the bottom RDL is connected to the short-circuit output signal terminal 12 and the open-circuit output signal terminal 13 respectively.

[0030] The input signal tap 3 is also connected to two sets of symmetrically arranged TSV mutual inductors, each set of TSV mutual inductors includes two spiral TSV inductors connected in series (equivalent to Figure 2 The inductance Ls in the circuit, the mutual inductance of the two inductors Ls forms the inductance Lm).

[0031] like Figure 6 、 7 As shown, each spiral TSV inductor includes a TSV copper pillar 9, and the upper and lower layers of inductors RDL1 are connected end to end in sequence through the TSV copper pillar 9. The upper layer inductor RDL1 is located in the upper RDL silicon dioxide isolation layer 18, and the lower layer inductor RDL1 is located in the lower RDL silicon dioxide isolation layer 11. Figure 8 As shown, the outer layer of the TSV copper pillar 9 is wrapped with a TSV isolation layer 6 , and the TSV isolation layer 6 is in contact with the silicon substrate 10 .

[0032] Each group of TSV mutual inductance is connected in parallel to the power divider input capacitor 2 and the power divider GND connection capacitor 8 (equivalent to Figure 2 The power divider GND is connected to the capacitor 8 and is connected to the GND4 in the upper RDL silicon dioxide isolation layer 18. The GND4 in the upper RDL silicon dioxide isolation layer 18 is connected to the GND4 in the lower RDL silicon dioxide isolation layer 11 through the TSV 14 connecting the upper and lower GNDs.

[0033] like Figure 9 As shown, a power divider capacitor dielectric layer silicon nitride 17 is provided between the upper plate and the lower plate of the power divider GND connected capacitor 8 .

[0034] Except for the RDL coupler structure composed of the coupler input signal layer 5 of the bottom RDL and the coupler output signal layer 7 of the bottom RDL, the rest of the structure is realized as follows: Figure 2 The power divider part.

[0035] Example 2

[0036] Based on Example 1, the present invention implements a dual-band power splitter balun based on TSV, including the following steps:

[0037] The input signal is divided into two paths by the input signal tap 3 and enters two symmetrically set power divider input capacitors 2, and is transmitted to the power divider isolation resistor 16 through the power divider input capacitor 2, and plays an output isolation role through the power divider isolation resistor 16; at the same time, the input signal enters the power divider GND from the input signal tap 3 and connects to the upper plate of the capacitor 8, and then passes through the capacitor dielectric layer silicon nitride 17 to reach the power divider GND and connect to the lower plate of the capacitor 8 and the GND4 of the top layer RDL to make the RDL inductor 1 generate mutual inductance, and make this part equivalent to two transmission lines of different frequencies. This part is the dual-band power divider part, and the isolated signal at both ends of the power divider isolation resistor 16 is connected to the power divider through the power divider isolation resistor 16. The TSV15 of the splitter output and the coupler input is transmitted to the RDL coupler, first passing through the coupler input signal layer 5 of the bottom RDL to generate a wide-side coupling signal and reaching the coupler output signal layer 7 of the bottom RDL, generating an output coupling signal that is output by the short-circuit output signal terminal 12 and the open-circuit output signal terminal 13. The short-circuit output signal terminal 12 is respectively connected to the GND4 located in the upper RDL silicon dioxide isolation layer 18 and the GND4 located in the lower RDL silicon dioxide isolation layer 11 to form a short circuit, providing a -90° phase difference of the balun, and the open-circuit output signal terminal 13 is left open to provide a +90° phase difference of the balun, thereby realizing a dual-band balun with an output phase difference of 180°.

[0038] Example 3

[0039] The main design parameters of the balun are as follows: Figure 1 The impedance of the λ / 4 wavelength transmission line is 70.71Ω and the electrical length is 90° / 270°, which is converted to Figure 2 The input capacitance 2Cp of the power divider is 0.161fF, the GND connection capacitance 8Cs of the power divider is 0.525fF, the RDL inductor 1Ls is 1.46nH, and the coupling mutual inductance Lm between the RDL inductors is 0.147nH. The common mode impedance Ze between the coupler input signal layer (5) and the coupler output signal layer (7) is 120.91Ω, the differential mode impedance Zo is 20.67Ω, and the electrical length is 90°.

[0040] The simulation results of the balun designed according to the above parameters are as follows Figure 10 and Figure 11 As shown, Figure 10 is the S-parameter diagram of the balun, with operating frequencies of 5 and 12 GHz respectively, where S11 is the return loss of the input signal tap 3, S12 is the insertion loss from the input signal tap 3 to the short-circuit output signal terminal 12, S13 is the insertion loss from the input signal tap 3 to the open-circuit output signal terminal 13, and S23 is the isolation between the short-circuit output signal terminal 12 and the open-circuit output signal terminal 13 after the power divider isolation resistor 16 is added.

[0041] Figure 11 Figure 1 is the balun output phase diagram, where S12 is the phase result generated by the short-circuited output signal terminal 12, and S13 is the phase result generated by the open-circuited output signal terminal 13. It can be observed that the phase difference between S12 and S13 within the operating frequency range is 180°, which meets the working requirements.

Claims

1. A dual-band power splitter balun based on TSV, characterized by: The invention comprises an upper RDL silicon dioxide isolation layer (18), a silicon substrate (10) and a lower RDL silicon dioxide isolation layer (11) which are sequentially arranged from top to bottom. An RDL coupler is arranged in the lower RDL silicon dioxide isolation layer (11). The RDL coupler is connected to two symmetrically arranged power divider input capacitors (2) via a TSV (15) connecting the power divider output and the coupler input. Each power divider input capacitor (2) is respectively connected in parallel to a group of TSV mutual inductors and a power divider GND connection capacitor (8). The TSV mutual inductors and the power divider input capacitors (2) are both connected to an input signal tap (3). Each group of TSV mutual inductors includes two spiral TSV inductors connected in series. The two TSV inductors are connected in series and connected in parallel with the power divider GND connection capacitor (8). The power divider GND connection capacitor (8) is connected to the GND (4) located in the upper RDL silicon dioxide isolation layer (18). The GND (4) located in the upper RDL silicon dioxide isolation layer (18) is connected to the GND (4) located in the lower RDL silicon dioxide isolation layer (11) through the TSV (14) connecting the upper and lower GNDs.

2. The TSV-based dual-band power splitter balun according to claim 1, characterized in that: The upper plates of the two power divider input capacitors (2) are connected to the input signal tap (3), the lower plates of the two power divider input capacitors (2) are connected to the power divider isolation resistor (16), and the lower plates of the two power divider input capacitors (2) are connected to the RDL coupler through TSVs (15) connecting the power divider output and the coupler input.

3. The TSV-based dual-band power splitter balun according to claim 2, characterized in that: The RDL coupler comprises a bottom RDL coupler input signal layer (5) and a bottom RDL coupler output signal layer (7) coupled to each other, the bottom RDL coupler input signal layer (5) is connected to the TSV (15) of the coupler input, and the bottom RDL coupler output signal layer (7) is respectively connected to the short-circuit output signal end (12) and the open-circuit output signal end (13).

4. The method for realizing dual-band using a TSV-based dual-band power splitter balun according to claim 3, characterized in that: The process includes the following: The input signal is divided into two paths by the input signal tap (3) and enters two symmetrically set power divider input capacitors (2), and then enters the power divider isolation resistor (16) through the power divider input capacitor (2), and plays the role of output isolation through the power divider isolation resistor (16); the isolated signal at both ends of the power divider isolation resistor (16) is transmitted to the RDL coupler through the TSV (15) connecting the power divider output and the coupler input, and first passes through the coupler input signal layer (5) of the bottom RDL to generate a wide-side coupled signal to reach the coupler of the bottom RDL The output signal layer (7) generates an output coupling signal which is outputted by a short-circuit output signal terminal (12) and an open-circuit output signal terminal (13). The short-circuit output signal terminal (12) is respectively connected to the GND (4) located in the upper RDL silicon dioxide isolation layer (18) and the GND (4) located in the lower RDL silicon dioxide isolation layer (11) to form a short circuit, thereby providing a balun phase difference of -90°. The open-circuit output signal terminal (13) is left open to provide a balun phase difference of +90°, thereby realizing a dual-band balun with an output phase difference of 180°.

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