A new type of on-chip internally matched power amplifier

Abstract

This invention relates to a microwave integrated circuit chipset technology based on metal substrate integration. Multiple chips, matching circuits, and bias circuits are densely integrated onto a single metal substrate, interconnected via gold wires to create a chipset product with independent functionality. This technology eliminates the packaging materials and processes required for integrated circuits, reducing raw materials, significantly reducing size and weight, and lowering costs. Furthermore, the substrate is soldered to the component substrate, significantly alleviating the problem of device temperature increases associated with the increasing power density of power amplifiers as technology advances.

Description

Technical Field

[0001] The invention is a novel chip-type internally matched power amplifier, belonging to the technical field of power amplification. Background Art

[0002] With the development of third-generation GaN semiconductor device technology, the research and development of GaN microwave devices has increased, and engineering applications have begun. However, traditional power devices require tube and package packaging for use. Packaged tubes are generally large in size and weight. This limits the use of power amplifiers in such tube and package packaging for modern electronic equipment and communication systems, and platforms with high weight requirements.

[0003] Since power amplifiers are mainly used in phased array radar transmitters, a radar integrates tens of thousands of power amplifiers. In the airborne and shipborne fields, there are strict weight requirements for power amplifiers. Taking a 2048-channel phased array array as an example, the number of assembled power amplifiers is as many as 2048. For airborne and shipborne application platforms with strict weight requirements, more than 2,000 power amplifiers packaged in tubes and shells means a huge volume and mass. The large mass means higher energy consumption, and the large volume means more inconvenient transportation and maneuverability. Summary of the Invention

[0004] This invention proposes a new type of internal matching, aiming to address existing issues and overcome the size and weight limitations of existing technologies. The invention provides a miniaturized microwave on-chip internally matched power amplifier. This amplifier densely mounts one or more microwave integrated circuit chips, along with bias or matching circuits, onto a package carrier. Gold wires interconnect these components to create a chipset product with independent functionality. This amplifier offers advantages such as low cost, compact package size, and light weight, providing strong technical support for further miniaturization of electronic systems.

[0005] The technical solution of the present invention is: a novel chip-type internally matched power amplifier, which has a two-way combined output and a structure including two GaN power tubes, two groups of internally matched passive input circuits, and two groups of internally matched passive output circuits. Each group of internally matched passive input circuits includes an impedance matching circuit, a gate bias circuit, and an isolation resistor, and each group of internally matched passive output circuits includes an impedance matching circuit, a drain bias circuit, and an isolation resistor. The GaN power tubes, internally matched passive input circuits, and internally matched passive output circuits are all integrated on the same chip, and the components are interconnected by gold wire.

[0006] One end of the internal matching passive input circuit is connected in series with the C2 capacitor and connected to the input port through a gold wire. The other end is matched in parallel with the C6a grounding capacitor and the C6b grounding capacitor through a gold wire, and is connected in series with the input end of the GaN power tube core through a gold wire.

[0007] One end of the internal matching passive output circuit is connected in series with the C5 capacitor and connected to the output port through a gold wire. The other end is matched in parallel with the C7a grounding capacitor and the C7b grounding capacitor through a gold wire, and is connected in series to the output end of the GaN power tube core through a gold wire.

[0008] One end of the impedance matching circuit is connected to the circuit input and output ends, and the other end is connected to the GaN power tube through a gold wire; the internal matching passive input circuit is connected in series with an R2 isolation resistor, and the internal matching passive output circuit is connected in series with an R3 isolation resistor. The R2 isolation resistor and R3 isolation resistor are thin film resistors that isolate the upper and lower power tubes; the gate bias circuit is connected in series with a thin film resistor to increase the low-frequency stability of the circuit, and is connected in parallel with a grounding capacitor to filter power supply noise.

[0009] The bias circuit is a quarter-wavelength choke line, which is connected to the matching circuit through a gold wire, and the gold wire is also connected in parallel with a grounding capacitor C1, a grounding capacitor C3, and a grounding capacitor C4.

[0010] The connection points of the C1 grounding capacitor, the C3 grounding capacitor, and the C4 grounding capacitor are as close as possible to the input and output capacitors.

[0011] The carrier is a molybdenum-copper carrier.

[0012] The GaN power tube is a GaN HEMT tube core.

[0013] The isolation resistor, impedance matching circuit, and gate bias circuit are all made on a ceramic substrate, and the ceramic substrate is 99.6% alumina ceramic.

[0014] The GaN power tube is a GaN HEMT tube core. The input ends of the two GaN power tubes are connected to the C6a multi-electrode single-layer grounding capacitor and the C6b multi-electrode single-layer grounding capacitor through gold wires. Then, gold wires are drawn from the C6a multi-electrode single-layer capacitor to connect to the internal matching passive input circuit 101. The internal matching passive input circuit 101 is made on a ceramic substrate and includes a C2 capacitor, a synthetic network with an impedance conversion function, and an R2 isolation resistor. The R2 isolation resistor is based on a thin film resistor on the ceramic board. The internal matching passive input circuit is connected to the input port through a gold wire drawn from the C2 capacitor. Similarly, the GaN The HEMT die has an output end connected to the C7a multi-electrode single-layer grounding capacitor and the C7b multi-electrode single-layer grounding capacitor via a gold wire, and then a gold wire is led out to connect to the internal matching passive output circuit 102. The internal matching passive output circuit 102 is fabricated on a ceramic substrate and includes a C5 capacitor, a synthetic network with an impedance conversion function, and an R3 isolation resistor. The R3 isolation resistor is a thin-film resistor on the ceramic substrate. The peripheral gate bias circuit increases the circuit's low-frequency stability by connecting the R1 resistor in series. One end of the gate bias circuit is connected to the C1 grounding capacitor in parallel via a gold wire, and then connected to the gate power supply. The other end is connected to the internal matching passive input circuit 101 via a gold wire. One end of the drain bias circuit is connected to the C3 grounding capacitor and the C4 grounding capacitor in parallel, and then connected to the drain power supply. The other end is connected to the internal matching passive output circuit 102.

[0015] Beneficial effects of the present invention:

[0016] 1) Since the chip-type power amplifier has no packaging shell, all chips and components are exposed on a chip, which makes the circuit design more flexible and can meet the needs of different situations.

[0017] 2) The size of the chip-mounted power amplifier is several tenths of that of the traditional tube-shell package, which greatly saves device assembly space and reduces device weight.

[0018] 3) The carrier is made of molybdenum copper, which has a similar thermal expansion coefficient to GaN. Compared with oxygen-free copper, the chip is less likely to break in high and low temperature environments. At the same time, it maintains a higher thermal conductivity. Combined with the natural exposed structure, it is more conducive to the heat dissipation of the device and maintains the thermal stability of the device.

[0019] 4) Due to the large die size of the high-power amplifier, the input impedance is low. By integrating a synthetic network with impedance transformation into the input circuit, the matching difficulty is reduced and the low-frequency stability and in-band stability are improved.

[0020] 5) The input and output ends of the tube core are interconnected with the ceramic thin film circuit through gold wire to form an inductor, and then connected in series with a multi-electrode single-layer capacitor to ground, which improves the adjustability of the circuit, suppresses the second harmonic, and optimizes the output capability of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the schematic diagram of the chip-mounted internal matching power tube circuit;

[0022] Figure 2 This is the circuit layout of the on-chip matching power tube.

[0023] In the figure, C1, C2, C3, C4, C5, C6a, C6b, C7a, and C7b are capacitors, 101 and 102 are circuits, R1, R2, and R3 are resistors, 4 is a GaN power tube, and 1 is a carrier. DETAILED DESCRIPTION

[0024] The on-chip internally matched amplifier circuit achieves miniaturization by densely mounting the power chip, impedance matching circuit, and bias circuit onto a package carrier and interconnecting the components via gold wire. Furthermore, utilizing limited design space, a clever structure featuring separate compensation capacitors and inductors provides greater design flexibility. This separation reduces the length and inductance of the gold wire. Furthermore, the flexible adjustment of the capacitance value through the gold wire improves the amplifier's short-circuit capability against second harmonics, thereby enhancing the amplifier's RF efficiency.

[0025] With the increasing power demands of modern electronic systems, solid-state power amplifiers need to continuously improve their power output capabilities. Typically, two or more GaN power tubes are used in parallel to output power through power combining technology. This invention uses two large-gate-width GaN power tubes in parallel. Each pre-matched unit is interconnected with gold wire via a capacitor in an LC circuit. Simultaneously, the GaN tube cores are also interconnected using the same method. The output ends of the two GaN power tubes are connected in parallel with gold wire to a pre-matched output circuit, which is then connected to a combining network.

[0026] The structure includes a wafer, GaN power tubes, two groups of internally matched passive input circuits (1 and 2), and two groups of internally matched passive output circuits (1 and 2). Each group of internally matched passive input circuits includes an impedance matching circuit, a gate bias circuit, and an isolation resistor R2. Each group of internally matched passive output circuits includes an impedance matching circuit, a drain bias circuit, and an isolation resistor R3.

[0027] The power transistor is a GaN HEMT die. The impedance matching circuit has one end connected to the input (output) port and the other end connected to the power transistor via a gold wire (BW). Resistors R2 and R3 are thin-film resistors based on a ceramic substrate, which isolate the upper and lower power transistors. The gate bias circuit is connected in series with thin-film resistors to enhance the circuit's low-frequency stability. A parallel capacitor is connected to ground to filter power supply noise. The drain bias circuit also has a parallel capacitor connected to ground to filter power supply noise.

[0028] The carrier film is molybdenum copper;

[0029] One end of the passive input circuit is connected in series with capacitor C2 and connected to the input port through a gold wire. The other end is connected in parallel with matching grounding capacitors C6a and C6b through a gold wire and connected in series to the input end of the tube core through a gold wire.

[0030] One end of the passive output circuit is connected in series with capacitor C5 and connected to the output port through a gold wire. The other end is connected in parallel with matching grounding capacitors C7a and C7b through a gold wire and connected in series to the output end of the tube core through a gold wire.

[0031] The chip, matching circuit, and bias circuit are all integrated on the same carrier;

[0032] The bias circuit is a quarter-wavelength choke line, which is connected to the matching circuit through gold wire. At the same time, the capacitors C1, C3, and C4 are connected to the ground in parallel through gold wire;

[0033] All thin film resistors, impedance conversion circuits, and bias circuits are fabricated on a ceramic substrate made of 99.6% alumina ceramic.

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings.

[0035] The amplifier schematic is as follows Figure 1As shown, the novel on-chip internal matching power amplifier has two combined outputs. The input ends of the two GaN HEMT tube cores 4 are connected to the multi-electrode single-layer grounding capacitors C6a and C6b through gold wires BW, and then the gold wires are drawn from the multi-electrode single-layer capacitor C6a to connect to the input pre-matching circuit 101. The input pre-matching circuit (101) is made on a ceramic substrate and consists of a capacitor C2, a synthetic network with an impedance conversion function, and an isolation resistor R2. The resistor R2 is based on a thin film resistor on the ceramic board. The input pre-matching circuit 101 is connected to the input port through a gold wire drawn from the capacitor C2. Similarly, the output end of the GaN HEMT tube core 4 is connected to the multi-electrode single-layer grounding capacitors C7a and C7b through a gold wire BW, and then the gold wires are drawn from the multi-electrode single-layer capacitors C7a and C7b to connect to the input pre-matching circuit 102. The input pre-matching circuit 102 is made on a ceramic substrate and consists of a capacitor C5, a synthetic network with an impedance conversion function, and an isolation resistor R3. The resistor R3 is based on a thin film resistor on the ceramic board. Resistors R2 and R3 act as isolation capacitors to improve the isolation between the two dies and prevent signal crosstalk. The peripheral gate bias circuit increases the low-frequency stability of the circuit through a series resistor R1. After one end of the gate bias circuit is connected in parallel to the ground capacitor C1 through a gold wire, it is connected to the gate power supply, and the other end is connected to the matching circuit 101 through a gold wire; after one end of the drain bias circuit is connected in parallel to the ground capacitors C3 and C4, the drain power supply is connected, and the other end is connected to the matching circuit 102. Capacitors C1, C3, and C4 are power supply filter capacitors that can prevent power supply noise from affecting the circuit. At the same time, the drain-source bias line does not participate in matching, so there is no requirement for the connection position to the matching circuit, but the connection point should be as close as possible to the input and output capacitors to achieve beautiful symmetry.

[0036] Circuit board diagram Figure 2 As shown, the capacitors, pre-matching circuit, and die are all soldered to a molybdenum-copper substrate for excellent heat dissipation. The molybdenum-copper material's suitable thermal expansion coefficient matches that of the GaN die, enhancing device reliability. The input and output terminals are connected to external devices via gold wires. The built-in power bias line is a quarter-wavelength choke line, which ensures DC power to the die without participating in matching, isolating microwave signals from entering the low-frequency circuit.

[0037] Regarding the pre-matching circuit 101, because this circuit is a high-power tube core with a millimeter-level gate width, and the gate width is inversely proportional to the input characteristic impedance, the input characteristic impedance of the tube core is very small and it is not suitable to be directly matched to 50 ohms. Therefore, the present invention matches the input impedance of the tube core to 10 ohms through capacitors C6a, C6b and gold wire to form an LC network, and then realizes impedance transformation through the input pre-matching circuit 101, matching 10 ohms to 50 ohms to achieve better matching. At the same time, a large capacitor C2 is placed at the input end to isolate the low-frequency signal from the incoming signal source. The resistor connected in series with the bias circuit can greatly reduce the possibility of the tube core being unstable at low frequencies and generating self-excited oscillation. Similarly, the same is true for the output pre-matching circuit 102.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in the technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A new type of on-chip internally matched power amplifier, characterized by The chip-mounted internally matched power amplifier has two combined outputs and includes two GaN power tubes, two groups of internally matched passive input circuits, and two groups of internally matched passive output circuits. Each group of internally matched passive input circuits includes an impedance matching circuit, a gate bias circuit, and an isolation resistor, and each group of internally matched passive output circuits includes an impedance matching circuit, a drain bias circuit, and an isolation resistor. The GaN power tubes, internally matched passive input circuits, and internally matched passive output circuits are all integrated on the same chip, and the components are interconnected by gold wires. One end of the internal matching passive input circuit is connected in series with the C2 capacitor and connected to the input port through a gold wire. The other end is connected in parallel with the C6a grounding capacitor and the C6b grounding capacitor through a gold wire and is connected in series with the input end of the GaN power tube die through a gold wire. One end of the internal matching passive output circuit is connected in series with the C5 capacitor and connected to the output port through a gold wire. The other end is connected in parallel with the C7a grounding capacitor and the C7b grounding capacitor through a gold wire and is connected in series with the output end of the GaN power tube die through a gold wire. One end of the impedance matching circuit is connected to the circuit input and output ends, and the other end is connected to the GaN power tube through a gold wire; the internal matching passive input circuit is connected in series with an R2 isolation resistor, and the internal matching passive output circuit is connected in series with an R3 isolation resistor. The R2 isolation resistor and R3 isolation resistor are thin film resistors that isolate the upper and lower power tubes; the gate bias circuit is connected in series with a thin film resistor to increase the low-frequency stability of the circuit, and is connected in parallel with a grounding capacitor to filter power supply noise.

2. A novel on-chip internally matched power amplifier according to claim 1, characterized in that The bias circuit is a quarter-wavelength choke line, which is connected to the matching circuit through a gold wire, and the gold wire is also connected in parallel with a grounding capacitor C1, a grounding capacitor C3, and a grounding capacitor C4.

3. A novel on-chip internally matched power amplifier according to claim 2, characterized in that The connection points of the C1 grounding capacitor, the C3 grounding capacitor, and the C4 grounding capacitor are as close as possible to the input and output capacitors.

4. A novel on-chip internally matched power amplifier according to claim 1, characterized in that The carrier is a molybdenum-copper carrier.

5. The novel on-chip internally matched power amplifier according to claim 1, characterized in that The GaN power tube is a GaN HEMT tube core.

6. A novel on-chip internally matched power amplifier according to claim 1, characterized in that The isolation resistor, impedance matching circuit, and gate bias circuit are all made on a ceramic substrate, and the ceramic substrate is 99.6% alumina ceramic.

7. The novel on-chip internally matched power amplifier according to claim 1, characterized in that The GaN power tube is a GaN HEMT tube core. The input ends of the two GaN power tubes are connected to the C6a multi-electrode type single-layer grounding capacitor and the C6b multi-electrode type single-layer grounding capacitor through gold wires. Then, the gold wires are drawn out from the C6a multi-electrode type single-layer capacitor to connect to the internal matching passive input circuit (101). The internal matching passive input circuit (101) is made on a ceramic substrate and includes a C2 capacitor, a synthetic network with an impedance conversion function, and an R2 isolation resistor. The R2 isolation resistor is based on a thin film resistor on the ceramic board. The internal matching passive input circuit is connected to the input port through a gold wire drawn out from the C2 capacitor. Similarly, the GaN The HEMT tube core has an output end connected to a C7a multi-electrode type single-layer grounding capacitor and a C7b multi-electrode type single-layer grounding capacitor through a gold wire, and then a gold wire is led out to connect to an internal matching passive output circuit (102). The internal matching passive output circuit (102) is made on a ceramic substrate and includes a C5 capacitor, a synthetic network with an impedance conversion function, and an R3 isolation resistor. The R3 isolation resistor is based on a thin film resistor on the ceramic board. The peripheral gate bias circuit increases the low-frequency stability of the circuit by connecting the R1 resistor in series. After connecting one end of the gate bias circuit to the C1 grounding capacitor in parallel through a gold wire, it is connected to the gate power supply, and the other end is connected to the internal matching passive input circuit (101) through a gold wire. After connecting one end of the drain bias circuit to the C3 grounding capacitor and the C4 grounding capacitor in parallel, it is connected to the drain power supply, and the other end is connected to the internal matching passive output circuit (102).

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