A miniaturized low-loss slot-line differential power combiner in millimeter-wave band
By employing slotted line differential power combining technology in the millimeter-wave band, the imaginary part of the amplifier core output impedance is improved. Combined with slotted line to microstrip line conversion, the problems of high loss and large size in traditional differential power combining technology are solved, realizing a low-loss and miniaturized power combiner design suitable for high-performance millimeter-wave communication systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-02
AI Technical Summary
In the millimeter-wave band, traditional differential power combining technology suffers from high losses, large size, and is not suitable for ultra-wideband designs. In particular, transformer baluns and Marchand baluns perform poorly in the high-frequency band, resulting in low output power combining efficiency.
Using a 130nm SiGe process, a miniaturized, low-loss slotted differential power combiner is designed by increasing the imaginary part of the amplifier core output impedance and combining it with slotted line technology. By utilizing the slotted line to microstrip line conversion structure, the capacitance value is reduced and the amplifier structure is optimized to achieve microstrip to slotted line conversion.
It achieves low-loss, small-size differential power combining, suitable for high-performance millimeter-wave communication radar systems, improves the output power and gain of the power amplifier, and reduces the size of the combining network.
Smart Images
Figure CN122137354A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of microwave integrated circuit technology, specifically relating to a miniaturized, low-loss slot line differential power combining technology in the millimeter-wave band. Background Technology
[0002] Power amplifiers are core components in the construction of radio frequency transmitters. Their output power and gain are crucial to transmitter performance, directly determining the transmitter's operating distance and signal quality. The ultra-wideband characteristics of the millimeter-wave band make the design of future high-performance ultra-wideband transmitters somewhat feasible. However, due to the increased frequency, traditional microstrip lines and other components exhibit significant losses in microwave integrated circuits, limiting the output power of the power amplifier. Furthermore, the differential balance characteristics also affect the final power combining losses.
[0003] Traditional differential power combining techniques mainly include transformer baluns and Marchand baluns. Transformer baluns are widely used in the low-frequency band, but as the frequency increases, the size of transformer baluns further decreases, and the coupling characteristics between adjacent conductors further increase losses and imbalances. Furthermore, the band-stop characteristics of transformer baluns are not suitable for ultra-wideband designs. On the other hand, the Marchand balun has a low coupling ratio, and the use of positive feedback technology to improve transistor performance in the millimeter-wave band worsens the output impedance, making it difficult for the Marchand balun to achieve ideal impedance matching.
[0004] Therefore, although millimeter-wave frequency ranges offer a wide available bandwidth for gain, the output power combining loss is significant due to the deterioration of differential balun characteristics. Furthermore, the multi-channel combining techniques employed to achieve higher output power further increase the chip footprint. Therefore, there is a need to invent a small-sized, low-loss differential power combining network. Summary of the Invention
[0005] Technical Problem: To solve the above problems, this invention provides a miniaturized, low-loss slot line differential power combining technology in the millimeter-wave band. Specifically, by increasing the imaginary part of the amplifier core output impedance, the core gain of the power amplifier is improved while the size of the slot line terminal capacitor is significantly reduced.
[0006] Technical Solution: To solve the above problems, this invention proposes a miniaturized, low-loss slot line differential power combiner for the millimeter-wave band. It adopts a 130nm SiGe process and improves the gain of the power amplifier core by increasing the imaginary part of the amplifier core output impedance, while significantly reducing the size of the slot line terminating capacitor. It is suitable for the design of power amplifier chips in the transceiver link of high-performance millimeter-wave communication radar systems and has the advantages of small size and low loss.
[0007] The technical solution adopted is as follows: The synthesizer comprises a microstrip line, a slotted line, an amplifier, an input port, and an output port; wherein, the ninth microstrip line is T-shaped, the output port is connected to the middle of the ninth microstrip line, and the two ends of the ninth microstrip line are two symmetrical paths with the same structure, one path is connected to the first microstrip line in the first amplifier network through the tenth and eleventh microstrip lines; the other path is connected to the fourth microstrip line in the second amplifier network through the eighth and seventh microstrip lines.
[0008] The first amplifier network includes a first slot line, a second slot line, a third slot line, a first microstrip line, a second microstrip line, a third microstrip line, a first amplifier, a second amplifier, a third amplifier, and a fourth amplifier. The second and third microstrip lines are two symmetrical U-shaped structures. The first microstrip line is a straight line located between the second and third microstrip lines. The third slot line is a straight line located below the first, second, and third microstrip lines and is perpendicularly coupled to them. The first and second slot lines are connected to the two ends of the third slot line. The output terminals of the first, second, third, and fourth amplifiers are connected to the four ports of the two symmetrical U-shaped second and third microstrip lines.
[0009] The second amplifier network includes a fourth slot line, a fifth slot line, a sixth slot line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a fifth amplifier, a sixth amplifier, a seventh amplifier, and an eighth amplifier. The fifth and sixth microstrip lines are two symmetrical U-shaped lines. The fourth microstrip line is a straight line located between the fifth and sixth microstrip lines. The sixth slot line is a straight line located below the fourth, fifth, and sixth microstrip lines and is perpendicularly coupled to them. The fourth and fifth slot lines are connected to the two ends of the sixth slot line. The outputs of the fifth, sixth, seventh, and eighth amplifiers are connected to the four ports of the two symmetrical U-shaped fifth and sixth microstrip lines.
[0010] The first, second, fourth, and fifth slots are hollow rectangles.
[0011] The input terminals of the first amplifier, second amplifier, third amplifier, and fourth amplifier are connected to the first input port, second input port, third input port, and fourth input port, respectively; the input terminals of the fifth amplifier, sixth amplifier, seventh amplifier, and eighth amplifier are connected to the fifth input port, sixth input port, seventh input port, and eighth input port, respectively.
[0012] The first amplifier and the second amplifier form a differential pair; the outputs of the first amplifier and the second amplifier are connected through a second microstrip line and coupled to a third slot line at a center tap to achieve microstrip-to-slot line conversion. The first slot line provides the capacitance required for the microstrip-to-slot line conversion. Similarly, the third amplifier and the fourth amplifier form a differential pair; the outputs of the third amplifier and the fourth amplifier are connected through a third microstrip line and coupled to a third slot line at a center tap to achieve microstrip-to-slot line conversion. The second slot line provides the capacitance required for the microstrip-to-slot line conversion. The third slot line and the first microstrip line form a coupling structure to achieve slot line-to-microstrip conversion; and the outputs are led out to the ninth microstrip line through the tenth microstrip line and the eleventh microstrip line.
[0013] The groove structure consists of four thin metal layers at the bottom, namely the first thin metal, the second thin metal, the third thin metal, and the fourth thin metal, and a thick metal layer at the top. Metal vias are provided between each metal layer, and the microstrip line is located above the thick metal layer at the top.
[0014] The first amplifier, second amplifier, third amplifier, and fourth amplifier adopt a common-emitter common-base amplification structure using transistors. A large capacitor is used at the base to enhance the imaginary part of the output impedance, further reducing the size of the first slot line, second slot line, fourth slot line, and fifth slot line.
[0015] The microstrip lines, slot lines, and amplifiers are all fabricated using silicon-based semiconductor integrated circuit technology. Beneficial effects
[0016] 1) By adopting slot line technology, a more ideal differential to single-ended conversion characteristic is achieved, further reducing output synthesis loss.
[0017] 2) By increasing the output imaginary impedance of the amplifier core, the capacitance required for the microstrip to slot line conversion of the output synthesis network is effectively reduced, thus achieving a miniaturized design.
[0018] 3) It is suitable for the core design of high-performance power amplifiers in microwave communication systems, and features low output loss and small size. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the miniaturized low-loss slotted differential power combining network for the millimeter-wave band of the present invention. Figure 2 This is a schematic diagram of the groove and microstrip stacked structure of the present invention; Figure 3 The loss of the W-band power amplifier combining network designed using this invention; Figure 4 These are the small-signal simulation results of the W-band power amplifier designed using this invention; Figure 5These are the large-signal simulation results of the W-band power amplifier designed using this invention; The image contains: First microstrip line MLIN1, second microstrip line MLIN2, third microstrip line MLIN3, fourth microstrip line MLIN4, fifth microstrip line MLIN5, sixth microstrip line MLIN6, seventh microstrip line MLIN7, eighth microstrip line MLIN8, ninth microstrip line MLIN9, tenth microstrip line MLIN10, eleventh microstrip line MLIN11. First slot line SLOT1, second slot line SLOT2, third slot line SLOT3, fourth slot line SLOT4, fifth slot line SLOT5, third slot line SLOT6; First amplifier PA1, second amplifier PA2, third amplifier PA3, fourth amplifier PA4, fifth amplifier PA5, sixth amplifier PA6, seventh amplifier PA7, eighth amplifier PA8; First input port Port1, second input port Port2, third input port Port3, fourth input port Port4, fifth input port Port5, sixth input port Port6, seventh input port Port7, eighth input port Port8, output port Port9; It consists of a first thin metal M1, a second thin metal M2, a third thin metal M3, a fourth thin metal M4, a second-layer thick metal M5, and a microstrip line M6. Detailed Implementation
[0020] This invention designs a miniaturized, low-loss slotted differential power combining network for the millimeter-wave band, comprising eight RF input ports and one RF output port. The circuit consists of two symmetrically distributed branches, each with a power amplifier core differentially distributed, and differential power combining is achieved through microstrip lines, slotted lines, and the conversion structures between them.
[0021] Each branch contains four power amplifier cores and performs power combining. Specifically, the first input port Port1 connects to the first amplifier PA1, and the second input port Port2 connects to the second amplifier PA2, forming a differential pair. The outputs of the first amplifier PA1 and the second amplifier PA2 are connected through the second microstrip line MLIN2 and coupled to the third slot line SLOT3 at the center tap to achieve microstrip-to-slot line conversion. The first slot line SLOT1 provides the capacitance required for the microstrip-to-slot line conversion. Similarly, the third input port Port3 connects to the third amplifier PA3, and the fourth input port Port4 connects to the fourth amplifier PA4, forming a differential pair. The outputs of the third amplifier PA3 and the fourth amplifier PA4 are connected through the third microstrip line MLIN3 and coupled to the third slot line SLOT3 at the center tap to achieve microstrip-to-slot line conversion. The second slot line SLOT2 provides the capacitance required for the microstrip-to-slot line conversion. The third slot line SLOT3 and the first microstrip line MLIN1 form a coupling structure to achieve slot line-to-microstrip conversion. The conversion is then led out to the ninth microstrip line MLIN9 through the fifth microstrip line MLIN5 and the sixth microstrip line MLIN6.
[0022] This invention achieves a more ideal differential-to-single-ended conversion characteristic by employing slotted-line technology, further reducing output combining loss. By increasing the output imaginary impedance of the amplifier core, the capacitance required for the microstrip-to-slotted conversion of the output combining network is effectively reduced, enabling miniaturized design. This combining structure is suitable for high-performance power amplifier core designs in microwave communication systems, offering advantages such as low output loss and small size.
[0023] The invention will now be further described with reference to the accompanying drawings.
[0024] like Figure 1 As shown, a miniaturized, low-loss slotted line differential power combiner for millimeter-wave frequencies is disclosed. The combiner comprises a microstrip line, a slotted line, an amplifier, an input port, and an output port. The ninth microstrip line, MLIN9, is T-shaped, and the output port, Port9, is connected to the middle of MLIN9. MLIN9 has two symmetrical paths with identical structures at its two ends. One path connects to the first microstrip line MLIN1 in the first amplifier network via the tenth microstrip line MLIN10 and the eleventh microstrip line MLIN11; the other path connects to the fourth microstrip line MLIN4 in the second amplifier network via the eighth microstrip line MLIN8 and the seventh microstrip line MLIN7.
[0025] The miniaturized, low-loss slotted differential power combiner for the millimeter-wave band has the following first branch sequentially connected: a first input port (Port1) connects to a first amplifier (PA1), and a second input port (Port2) connects to a second amplifier (PA2), forming a differential pair. The outputs of the first amplifier (PA1) and the second amplifier (PA2) are connected via a second microstrip line (MLIN2) and coupled to a third slotted line (SLOT3) at a center tap to achieve microstrip-to-slot conversion. The first slotted line (SLOT1) provides the capacitance required for this microstrip-to-slot conversion. Similarly, a third input port (Port3) connects to a third amplifier (PA3), and a fourth input port (Port4) connects to a fourth amplifier (PA4), forming a differential pair. The outputs of the third amplifier (PA3) and the fourth amplifier (PA4) are connected via a third microstrip line (MLIN3) and coupled to a third slotted line (SLOT3) at a center tap to achieve microstrip-to-slot conversion. The second slotted line (SLOT2) provides the capacitance required for this microstrip-to-slot conversion. The third slotted line (SLOT3) and the first microstrip line (MLIN1) form a coupling structure to achieve slotted-to-microstrip conversion. The outputs are then led out to a ninth microstrip line (MLIN9) via a fifth microstrip line (MLIN5) and a sixth microstrip line (MLIN6).
[0026] like Figure 2 As shown, the miniaturized low-loss slotted differential power combining technology in the millimeter-wave band consists of a slotted structure composed of four bottom thin metal layers, namely the first thin metal M1, the second thin metal M2, the third thin metal M3, and the fourth thin metal M4, and a second top thick metal M5. Metal vias are provided between each metal, and the microstrip line M6 is located above the second top thick metal M5.
[0027] The miniaturized, low-loss slot line differential power combining technology for millimeter-wave bands is characterized in that the core of the power amplifier adopts a common-emitter, common-base amplification structure using a transistor, and a large capacitor is used at the base to enhance the output imaginary impedance, further reducing the size of the first slot line SLOT1, the second slot line SLOT2, the fourth slot line SLOT4, and the fifth slot line SLOT5.
[0028] The microstrip lines, slot lines, and amplifiers are all fabricated using silicon-based semiconductor integrated circuit technology.
[0029] The miniaturized, low-loss slotted differential power combining technology for the millimeter-wave band is characterized in that the slotted line is converted to a microstrip line, and the slotted line and the microstrip line are vertically coupled to reduce conversion loss.
[0030] Figure 3 This is a simulation result of the insertion loss of this invention applied to a W-band power amplifier circuit. Within the desired frequency range of 75-110 GHz, the loss of this synthesized network is approximately 1 dB.
[0031] Figure 4This invention is applied to the small-signal simulation results of a W-band power amplifier. The invention achieves a 3dB coverage range of 65-119GHz while maintaining relatively excellent S11 and S22 characteristics.
[0032] Figure 5 This invention is applied to the simulation results of large-signal power amplifiers in the W-band. The invention achieves a full-band output power greater than 20 dBm within the 75-110 GHz range, with a peak power reaching 23 dBm.
[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies, characterized in that, The synthesizer comprises microstrip lines, slotted lines, amplifiers, input ports, and output ports. The ninth microstrip line (MLIN9) is T-shaped, and the output port (Port9) is connected in the middle of the ninth microstrip line (MLIN9). The two ends of the ninth microstrip line (MLIN9) are two symmetrical paths with the same structure. One path is connected to the first microstrip line (MLIN1) in the first amplifier network through the tenth microstrip line (MLIN10) and the eleventh microstrip line (MLIN11); the other path is connected to the fourth microstrip line (MLIN4) in the second amplifier network through the eighth microstrip line (MLIN8) and the seventh microstrip line (MLIN7).
2. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 1, characterized in that, The first amplifier network includes a first slot line (SLOT1), a second slot line (SLOT2), a third slot line (SLOT3), a first microstrip line (MLIN1), a second microstrip line (MLIN2), a third microstrip line (MLIN3), a first amplifier (PA1), a second amplifier (PA2), a third amplifier (PA3), and a fourth amplifier (PA4); wherein the second microstrip line (MLIN2) and the third microstrip line (MLIN3) are two symmetrical U-shaped structures, the first microstrip line (MLIN1) is a straight line located between the second microstrip line (MLIN2) and the third microstrip line (MLIN3); the third slot line (SLOT3)... It is a straight line, located below the first microstrip line (MLIN1), the second microstrip line (MLIN2), and the third microstrip line (MLIN3) and vertically coupled to them; the first slot line (SLOT1) and the second slot line (SLOT2) are respectively connected to the two ends of the third slot line (SLOT3); the output terminals of the first amplifier (PA1), the second amplifier (PA2), the third amplifier (PA3), and the fourth amplifier (PA4) are respectively connected to the four ports of the two symmetrical U-shaped second microstrip lines (MLIN2) and the third microstrip line (MLIN3).
3. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 1, characterized in that, The second amplifier network includes a fourth slot line (SLOT4), a fifth slot line (SLOT5), a sixth slot line (SLOT6), a fourth microstrip line (MLIN4), a fifth microstrip line (MLIN5), a sixth microstrip line (MLIN6), a fifth amplifier (PA5), a sixth amplifier (PA6), a seventh amplifier (PA7), and an eighth amplifier (PA8). The fifth microstrip line (MLIN5) and the sixth microstrip line (MLIN6) are two symmetrical U-shaped structures, and the fourth microstrip line (MLIN4) is a straight line located between the fifth microstrip line (MLIN5) and the sixth microstrip line (MLIN6). The sixth slot line (SLOT6)... It is a straight line, located below the fourth microstrip line (MLIN4), the fifth microstrip line (MLIN5), and the sixth microstrip line (MLIN6), and is vertically coupled to the fourth microstrip line (MLIN4), the fifth microstrip line (MLIN5), and the sixth microstrip line (MLIN6); the fourth slot line (SLOT4) and the fifth slot line (SLOT5) are respectively connected to the two ends of the sixth slot line (SLOT6); the output terminals of the fifth amplifier (PA5), the sixth amplifier (PA6), the seventh amplifier (PA7), and the eighth amplifier (PA8) are respectively connected to the four ports of the fifth microstrip line (MLIN5) and the sixth microstrip line (MLIN6) in two symmetrical U-shapes.
4. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 2 or 3, characterized in that, The first slot (SLOT1), the second slot (SLOT2), the fourth slot (SLOT4), and the fifth slot (SLOT5) are hollow rectangles.
5. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 2 or 3, characterized in that, The input terminals of the first amplifier (PA1), the second amplifier (PA2), the third amplifier (PA3), and the fourth amplifier (PA4) are connected to the first input port (Port1), the second input port (Port2), the third input port (Port3), and the fourth input port (Port4), respectively; the input terminals of the fifth amplifier (PA5), the sixth amplifier (PA6), the seventh amplifier (PA7), and the eighth amplifier (PA8) are connected to the fifth input port (Port5), the sixth input port (Port6), the seventh input port (Port7), and the eighth input port (Port8), respectively.
6. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 5, characterized in that, The first amplifier (PA1) and the second amplifier (PA2) form a differential pair transistor; the outputs of the first amplifier (PA1) and the second amplifier (PA2) are connected through the second microstrip line (MLIN2) and coupled to the third slot line (SLOT3) at the center tap to realize the microstrip-to-slot line conversion; the first slot line (SLOT1) provides the capacitance required for the microstrip-to-slot line conversion. Similarly, the third amplifier (PA3) and the fourth amplifier (PA4) form a differential pair; the outputs of the third amplifier (PA3) and the fourth amplifier (PA4) are connected through the third microstrip line (MLIN3) and coupled to the third slot line (SLOT3) at the center tap to realize the microstrip to slot line conversion. The second slot line (SLOT2) provides the capacitance required for the microstrip to slot line conversion; the third slot line (SLOT3) and the first microstrip line (MLIN1) form a coupling structure to realize the slot line to microstrip conversion; and it is led out to the ninth microstrip line (MLIN9) through the tenth microstrip line (MLIN10) and the eleventh microstrip line (MLIN11).
7. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 2, characterized in that, The groove structure consists of four bottom thin metal layers, namely the first thin metal (M1), the second thin metal (M2), the third thin metal (M3), and the fourth thin metal (M4), and the second top thick metal (M5). Metal vias are provided between each metal layer, and the microstrip line (M6) is located above the second top thick metal (M5).
8. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 6, characterized in that, The first amplifier (PA1), the second amplifier (PA2), the third amplifier (PA3), and the fourth amplifier (PA4) adopt a common-emitter common-base amplification structure using transistors. A large capacitor is used at the base to enhance the imaginary part of the output impedance, further reducing the size of the first slot line (SLOT1), the second slot line (SLOT2), the fourth slot line (SLOT4), and the fifth slot line (SLOT5).
9. The miniaturized, low-loss slotted differential power combiner for millimeter-wave frequencies according to claim 1, characterized in that, The microstrip lines, slot lines, and amplifiers are all fabricated using silicon-based semiconductor integrated circuit technology.