KR100638740B1 - DC modeling method of high frequency single integrated circuit amplifier - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a DC modeling method of a high frequency single integrated circuit amplifier.

2. The technical problem to be solved by the invention

It is an object of the present invention to provide a DC modeling method of an MMIC amplifier for modeling a DC element matching a DC characteristic at an operating point of the MMIC amplifier by changing only some parameter values of the parameters of the FET.

3. Summary of Solution to Invention

The present invention provides a DC modeling method of a monolithic microwave integrated circuit (MMIC) amplifier using a simulator, the method comprising: measuring gate voltage and drain voltage of an MMIC amplifier for optimizing RF performance of the MMIC amplifier; Maintaining the gate voltage, varying the drain voltage and measuring a drain current value; And adjusting and modeling a parameter of a DC model in which the drain current changes according to the change of the gate voltage to approximate the drain voltage / current characteristic of the measured gate voltage based on the measured data.

4. Important uses of the invention

The present invention is used for DC modeling of MMIC amplifiers.

MMIC Amplifier, DC Models, FETs, Beta, Lamda

Description

DC modeling method of a high frequency single integrated circuit amplifier {Method for DC modeling of MMIC amplifier}             

1 is a general bias circuit diagram for driving a high frequency integrated circuit (Monolithic Microwave Integrated Circuit (MMIC)) amplifier,

2 is a configuration diagram of an embodiment of a MMIC LNA measuring jig for measuring DC characteristics of a MMIC low noise amplifier;

3 is a diagram illustrating a structure of a P-SPICE of a field effect transistor (FET) for DC modeling an MMIC LNA according to an embodiment of the present invention;

4A is a view for explaining model parameters of a FET before DC modeling for an MMIC LNA according to an embodiment of the present invention;

4B is a view for explaining model parameters of a FET after DC modeling for an MMIC LNA according to an embodiment of the present invention;

Figure 5 is a graph comparing the DC characteristics of the MMIC LNA measurement data and MMIC LNA DC model of the FET according to an embodiment of the present invention,

6 is a graph illustrating drain voltage / current characteristics of a plurality of gate voltages of an MMIC LNA according to an exemplary embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

110, 120: voltage source 130: MMIC amplifier

140, 310: gate 150, 320: drain

210: MMIC LNA 220: Input Port

230: output port 240: gate power pin

250: drain power pin 330: source

340: gate voltage source 350: drain voltage source

The present invention relates to a DC modeling method of a monolithic microwave integrated circuit (MMIC) amplifier, and more particularly to a DC modeling of a MMIC amplifier using a field effect transistor (FET). The present invention relates to a DC modeling method of an MMIC amplifier.

The MMIC amplifier is an amplifier in which various individual devices are implemented on a single chip, which has excellent high frequency characteristics and little characteristic change according to the strength of an RF (Radio Frequency) signal.

The MMIC amplifier is composed of three ports, a ground, a gate, and a drain, and has a characteristic of changing the drain current according to the voltage of the gate.

In general, in order to develop a part, the circuit design for that part must be performed first. After the design is completed, the functional test and performance test of the circuit are performed.

The functional test and the performance test of the circuit, that is, a circuit analysis method, include an equivalent circuit and a computer simulator.

The circuit analysis method using an equivalent circuit is to implement a circuit on a breadboard and then analyze the circuit by replacing all individual elements constituting the actual circuit with the elements having the same function.

In the circuit analysis method using an equivalent circuit, the function of the individual elements of the circuit implemented on the test board does not exactly match all the individual elements constituting the actual circuit, and in case of error in the circuit design, the internal signals of the individual elements are checked. There is a difficulty in circuit analysis.

The circuit analysis method using a circuit simulator in a computer finds a model of an individual element constituting a circuit in a simulator and implements and analyzes a circuit. SPICE is the most widely used simulator.

One important aspect of implementing an MMIC amplifier is the development of a bias board to bias the MMIC amplifier. Developing a bias board requires designing a bias circuit and interpreting the circuit.

Circuit simulation using a simulator of a bias circuit to drive an MMIC amplifier is to find and implement a model of the MMIC amplifier that serves as a load of the bias circuit and the individual elements constituting the bias circuit, and obtain a DC operating point.

At this time, in order to analyze the circuit of the bias circuit using a simulator, an accurate model of each device used for the circuit analysis is required. There is no exact model that matches the DC characteristics of the MMIC amplifier serving as a load of the bias circuit.

Therefore, in order to analyze the bias circuit, a model matching the DC characteristics of the MMIC amplifier is required.

In general, two methods are used for DC modeling of MMIC amplifiers.

The first method is to find a FET model in the simulator that has values similar to the gate voltage and drain voltage / current values at the DC operating point of the MMIC amplifier.

However, the MMIC amplifier has a characteristic that the drain current changes according to the change of the gate voltage, and the FET model used in the simulator does not satisfy the characteristic.

In addition, DC characteristics caused by inaccuracies in the model must be further processed to make the characteristics similar by tuning the resistance values after fabrication of the bias circuit.

The second method is to model a real MMIC amplifier by acquiring a large amount of measurement data according to the bias condition of the MMIC amplifier. However, it takes a lot of time and effort to obtain the measurement data.

On the other hand, Korean Patent Laid-Open Publication No. 1020027014414 proposes a modeling method for a High Electron Mobility Transistor (HEMT) which is a device for a high frequency amplifier. That is, the present invention proposes a modeling method that properly combines conventional equivalent circuit modeling and physical device simulation to provide a model having DC and RF characteristics that are close to DC and RF characteristics at various operating points of an actual HEMT device.

However, the disclosed patent can provide a model that is close to the DC and RF characteristics at various operating points of the actual HEMT device by using a complicated formula and theoretical modeling method, but at any one gate voltage and drain voltage. There is a disadvantage that the current value is not accurate.

The present invention has been proposed to solve the above problems, and by changing only some parameter values of the parameters of the FET, DC modeling method of the MMIC amplifier for modeling a DC element matching the DC characteristics at one operating point of the MMIC amplifier The purpose is to provide.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The method of the present invention for achieving the above object is a DC modeling method of a high frequency integrated circuit (MMIC) amplifier using a simulator, the gate voltage of the MMIC amplifier to optimize the RF performance of the MMIC amplifier Measuring the drain voltage; Maintaining the gate voltage, varying the drain voltage and measuring a drain current value; And adjusting and modeling a parameter of a DC model in which the drain current changes according to the change of the gate voltage to approximate the drain voltage / current characteristic of the measured gate voltage based on the measured data. .

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a general bias circuit diagram for driving an MMIC amplifier.

As shown in FIG. 1, the bias circuit is connected to the MMIC amplifier 130 serving as a load of the circuit, and using the voltage sources 110 and 120, the gate 140 and the drain of the MMIC amplifier 130 ( Supply voltage to 150).

The MMIC amplifier 130 has a characteristic in which the current of the drain 150 changes according to the voltage of the gate 140. Therefore, an amplifier model in which the current of the drain 150 changes according to the voltage change of the gate 140 is required. A DC device that satisfies these characteristics may be FET or HEMT, for example. For convenience of description, the following embodiment will be described using FET as an example.

First, in order to perform DC modeling of the MMIC amplifier 130 using the FET, the MMIC amplifier 130 needs to measure a DC operating point at which an optimal RF performance is achieved. Optimal RF performance herein means that it has maximum current gain and minimum return loss characteristics even at small currents.

In the following embodiment, a MMIC Low Noise Amplifier (LNA) of the MMIC amplifier is described as an example, but it is apparent to those skilled in the art that the technical idea of the present invention is not limited thereto.

Figure 2 is a configuration diagram of an embodiment of the MMIC LNA measuring jig for measuring the DC characteristics of the MMIC LNA.

As shown in FIG. 2, the MMIC LNA measuring jig includes input and output ports 220 and 230 for measuring RF characteristics of the MMIC LNA 210, a gate power pin 240 for driving the MMIC LNA 210, and A drain power pin 250 is included.

In order to measure the RF characteristics of the MMIC LNA 210, the input and output ports 220 and 230 are connected to an RF performance measuring device (not shown), and the gate for supplying a driving bias to the MMIC LNA 210. Drain power pins (240, 250) are connected to a DC power source.

Adjust the voltage of the DC power connected to the gate power pin 240 and the drain power pin 250 so that the RF performance measured by the RF performance measuring device is optimized, that is, the MMIC has maximum current gain and minimum return loss even at a small current. .

When a DC power supply having an optimal RF performance is obtained, the voltage of the DC power connected to the drain power pin 250 is changed by 0.05V while maintaining the voltage of the DC power connected to the gate power pin 240. Measure the drain current.

The measurement result of maintaining the voltage of the gate power supply, changing the voltage of the drain power supply, and measuring the drain current value accordingly is shown in FIG. 5 described later.

The above-described process for measuring the DC characteristics of the MMIC LNA must be followed to obtain optimal operation in the development of the MMIC and amplifier modules.

That is, in the conventional modeling technique, a lot of time and effort is required to measure data for modeling, but the modeling method according to the present invention requires the time and effort required in the conventional modeling technique by using data obtained naturally in the module development process. Not.

Next, the MMIC LNA performs DC modeling of the MMIC LNA 130 using a FET using a DC operating point showing optimal RF performance.

To model the DC, the simulator uses an electronic circuit simulator, P-SPICE.

3 is a P-SPICE diagram of a field effect transistor (FET) for DC modeling an MMIC LNA according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the FET includes a gate 310, a drain 320, and a source 330 electrode.

First, voltage sources 340 and 350 are connected to the gate 310 and drain 320 electrodes, and the source 330 electrode is grounded.

Thereafter, the voltage of the gate voltage source 340 is fixed to a voltage value representing the optimal RF performance measured by the MMIC low noise amplifier, and the drain current value is measured while increasing the voltage of the drain voltage source 350.

When the drain current value according to the change of the drain voltage value measured by simulating the FET is different from the drain current value according to the change of the drain voltage value of the MMIC LNA, the "Beta" value and "Lamda" among the model parameters of the FET "Adjust the value and repeat the simulation (Curve fitting).

The value of "Beta" among the model parameters of the FET affects the magnitude of the drain current, and the value of "Lamda" affects the amount of change of the current according to the amount of change of the drain voltage, that is, the slope.

4A and 4B are diagrams for explaining model parameters of a FET before and after DC modeling for an MMIC LNA according to an embodiment of the present invention.

As shown in FIGS. 4A and 4B, the "Beta" parameter value of the FET before DC modeling for MMIC LNA is 1.340m, the "Lamda" parameter value is 2.25m, and the "Beta" of FET after DC modeling for MMIC LNA "The parameter value is 2.500m and the" Lamda "parameter value is 1.25m.

The DC characteristic of the FET by the parameter after DC modeling is shown in FIG. 5 described later.

5 is a graph comparing the DC characteristics of the MMIC LNA measurement data and the MMIC LNA DC model of the FET according to an embodiment of the present invention.

As shown in FIG. 5, it can be seen that the measured data value 510 of the MMIC LNA measured in FIG. 2 and the DC characteristic 520 of the FET modeled DC in FIG. 4 coincide.

That is, the drain voltage / current characteristic of one gate voltage of the MMIC LNA and the parameter “Beta” and parameter “Lamma” are adjusted to match the drain voltage / current characteristic of one gate voltage of the FET modeling the MMIC LNA.

6 is a graph illustrating drain voltage / current characteristics of a plurality of gate voltages of an MMIC LNA according to an exemplary embodiment of the present invention.

In general, as shown in FIG. 6, the MMIC LNA has various drain voltage / current characteristics with respect to the gate voltage.

However, rather than a model that matches the drain voltage / current characteristics for all gate voltages of the MMIC LNA, a model that matches the drain voltage / current characteristics for one gate voltage is needed.

Therefore, as shown in FIG. 6, except for the box part, the DC characteristics of the actual MMIC LNA and the model may be different.

In addition, the modeling method according to the present invention can be applied to various types regardless of the type of the MMIC amplifier.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, by adjusting some parameters of the FET to match the DC characteristics of the FET to the DC characteristics of the MMIC amplifier, it is possible to DC model the MMIC amplifier with a simple operation.

Claims (4)

DC modeling method of a monolithic microwave integrated circuit (MMIC) amplifier using a simulator, Measuring, by the MMIC amplifier, the gate voltage and the drain voltage of the MMIC amplifier capable of obtaining maximum current gain and minimum return loss even at a small current; Maintaining the gate voltage, varying the drain voltage and measuring a drain current value; And Modeling by adjusting a parameter of a DC model in which the drain current changes according to the change of the gate voltage to match the drain voltage / current characteristic of the measured gate voltage based on the measured data. DC modeling method of a high frequency single integrated circuit amplifier comprising a. The method of claim 1, The DC model, Field Effect Transistors (FETs) DC modeling method of high frequency single integrated circuit amplifier. The method according to claim 1 or 2, The parameter is Parameters affecting the magnitude of the drain current, and parameters affecting the amount of change (tilt) of the current according to the amount of change in the drain voltage. DC modeling method of high frequency single integrated circuit amplifier. The method of claim 3, wherein The parameter affecting the magnitude of the drain current, "Beta" The parameter affecting the slope is, "Lamda" Inn DC modeling method of high frequency single integrated circuit amplifier.

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