Methods, systems, and computer-readable media for improving accuracy of network parameter in electromagnetic simulation and modeling

• US 8,682,625 B2
• Filed: 11/11/2011
• Issued: 03/25/2014
• Est. Priority Date: 11/11/2011
• Status: Active Grant

• Current Assignee: Sigrity Incorporated (Cadence Group)
• Original Assignee: Sigrity Incorporated (Cadence Group)
• Inventors: Fang, Jiayuan, Liu, Jian, Mao, Kaiyu
• Primary Examiner(s): Phan, Thai
• Application Number:
  US13/294,325
• Publication Number:
  US 20130124181A1
• Time in Patent Office: 865 Days
• Field of Search: 703/2, 703/14, 703/19
• US Class Current: 703/2
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

Method, system, and computer readable medium are disclosed for analyzing electrical properties of a circuit. The method may comprise: providing a network model including at least one network parameter, the network parameter being defined over a frequency range; converting the network parameter into an intermediate network parameter having first and second portions; identifying first and second frequencies defining a frequency sub-range; replacing the first portion of the intermediate network parameter with a DC value when a frequency associated with the intermediate network parameter is lower than the first frequency; replacing the first portion of the intermediate network parameter with a transitional value when the frequency associated with the intermediate network parameter is within the frequency sub-range; and converting the intermediate network parameter with the replaced first portion into an updated network parameter.

Claims

1. A method, implemented by a computer, for analyzing electrical properties of a circuit, the method comprising:

providing a network model of the circuit having at least one port, wherein the network model includes at least one network parameter, the network parameter being associated with the port and being defined over a frequency range;

converting, by the computer, the network parameter into an intermediate network parameter;

the intermediate network parameter having first and second portions;

providing a value indicative of an electrical property of the port in a direct current (DC) condition;

identifying first and second frequencies in the frequency range, the first frequency being lower than the second frequency, wherein the first and second frequencies define a frequency sub-range;

replacing the first portion of the intermediate network parameter with the value when a frequency associated with the intermediate network parameter is lower than the first frequency;

replacing the first portion of the intermediate network parameter with a transitional value when the frequency associated with the intermediate network parameter is within the frequency sub-range; and

converting, by the computer, the intermediate network parameter with the replaced first portion into an updated network parameter.

2. The method of claim 1, wherein the network parameter is selected from a group consisting of:

scattering parameters (S-parameters);

hybrid parameters (h-parameters);

inverse hybrid parameters (g-parameters);

transmission parameters (ABCD-parameters); and

scattering transfer parameters (T-parameters).

3. The method of claim 1, wherein the intermediate network parameter comprises impedance parameters (z-parameters).

4. The method of claim 3, wherein the value is a DC impedance of the port.

5. The method of claim 1, wherein the intermediate network parameter comprises admittance parameters (y-parameters).

6. The method of claim 5, wherein the value is a DC admittance of the port.

7. The method of claim 1, wherein the first and second portions of the intermediate network parameter are real and imaginary parts, respectively.

8. The method of claim 1, the step of identifying the first frequency further comprising:

identifying the first frequency based on a curve indicative of a variation of the first portion of the intermediate network parameter over the frequency range, wherein the first frequency is a frequency above which the curve becomes unflat.

9. The method of claim 1, the step of identifying the second frequency further comprising:

identifying the second frequency based on an inter-plane coupling frequency, wherein the inter-plane coupling frequency is determined by at least a thickness and a conductivity of a metal plane in a multi-plane structure of the circuit.

10. The method of claim 1, wherein the transitional value is calculated by at least one of:

a smoothing function and a polynomial function.

11. The method of claim 1, further comprising:

ensuring causality of the updated network parameter by changing the second portion of the intermediate network parameter based on Hilbert transform.

12. The method of claim 1, wherein:

the network model includes first and second ports and first and second network parameters, each of the first and second network parameters being associated with at least one of the first and second ports, the first network parameter being defined over a first frequency range, the second network parameter being defined over a second frequency range;

the step of converting the network parameter into the intermediate network parameter includes converting the first network parameter into a first intermediate network parameter and converting the second network parameter into a second intermediate network parameter; and

the step of identifying includes;

identifying third and fourth frequencies in the first frequency range, the third frequency being lower than the fourth frequency;

identifying fifth and sixth frequencies in the second frequency range, the fifth frequency being lower than the sixth frequency;

assigning a lower frequency of the third and fifth frequencies to the first frequency; and

assigning a higher frequency of the fourth and sixth frequencies to the second frequency.

13. A non-transitory computer-readable medium encoded with software code instructions, when executed by a computer, implementing a method for analyzing electrical properties of a circuit, the method comprising:

providing a network model of the circuit having at least one port, wherein the network model includes at least one network parameter, the network parameter being associated with the port and being defined over a frequency range;

converting, by the computer, the network parameter into an intermediate network parameter;

the intermediate network parameter having first and second portions;

providing a value indicative of an electrical property of the port in a direct current (DC) condition;

identifying first and second frequencies in the frequency range, the first frequency being lower than the second frequency, wherein the first and second frequencies define a frequency sub-range;

replacing the first portion of the intermediate network parameter with the value when a frequency associated with the intermediate network parameter is lower than the first frequency;

replacing the first portion of the intermediate network parameter with a transitional value when the frequency associated with the intermediate network parameter is within the frequency sub-range; and

converting, by the computer, the intermediate network parameter with the replaced first portion into an updated network parameter.

14. The non-transitory computer-readable medium of claim 13, wherein the network parameter is selected from a group consisting of:

scattering parameters (S-parameters);

hybrid parameters (h-parameters);

inverse hybrid parameters (g-parameters);

transmission parameters (ABCD-parameters); and

scattering transfer parameters (T-parameters).

15. The non-transitory computer-readable medium of claim 13, wherein the intermediate network parameter comprises impedance parameters (z-parameters).

16. The non-transitory computer-readable medium of claim 15, wherein the value is a DC impedance of the port.

17. The non-transitory computer-readable medium of claim 13, wherein the intermediate network parameter comprises admittance parameters (y-parameters).

18. The non-transitory computer-readable medium of claim 17, wherein the value is a DC admittance of the port.

19. The non-transitory computer-readable medium of claim 13, wherein the first and second portions of the intermediate network parameter are real and imaginary parts, respectively.

20. The non-transitory computer-readable medium of claim 13, wherein the method further comprises:

identifying the first frequency based on a curve indicative of a variation of the first portion of the intermediate network parameter over the frequency range, wherein the first frequency is a frequency above which the curve becomes unflat.

21. The non-transitory computer-readable medium of claim 13, wherein the method further comprises:

identifying the second frequency based on an inter-plane coupling frequency, wherein the inter-plane coupling frequency is determined by at least a thickness and a conductivity of a metal plane in a multi-plane structure of the circuit.

22. The non-transitory computer-readable medium of claim 13, wherein the transitional value is calculated by at least one of:

a smoothing function and a polynomial function.

23. The non-transitory computer-readable medium of claim 13, wherein the method further comprising:

ensuring causality of the updated network parameter by changing the second portion of the intermediate network parameter based on Hilbert transform.

24. The non-transitory computer-readable medium of claim 14, wherein the method further comprises:

providing the network model including first and second ports and first and second network parameters, each of the first and second network parameters being associated with at least one of the first and second ports, the first network parameter being defined over a first frequency range, the second network parameter being defined over a second frequency range;

converting the first network parameter into a first intermediate network parameter and converting the second network parameter into a second intermediate network parameter;

identifying third and fourth frequencies in the first frequency range, the third frequency being lower than the fourth frequency;

identifying fifth and sixth frequencies in the second frequency range, the fifth frequency being lower than the sixth frequency;

assigning a lower frequency of the third and fifth frequencies to the first frequency; and

assigning a higher frequency of the fourth and sixth frequencies to the second frequency.

25. A system for simulating electrical properties of a circuit, comprising:

a processor; and

a memory communicatively coupled to the processor,

wherein the processor is configured to;

load a network model of the circuit into the memory, wherein the network model includes at least one port and at least one network parameter, the network parameter being associated with the port and being defined over a frequency range;

convert the network parameter into an intermediate network parameter;

the intermediate network parameter having first and second portions;

obtain a value indicative of an electrical property of the port in a direct current (DC) condition;

identify first and second frequencies in the frequency range, the first frequency being lower than the second frequency, wherein the first and second frequencies define a frequency sub-range;

replace the first portion of the intermediate network parameter with the value when a frequency associated with the intermediate network parameter is lower than the first frequency;

replace the first portion of the intermediate network parameter with a transitional value when the frequency associated with the intermediate network parameter is within the frequency sub-range; and

convert the intermediate network parameter with the replaced first portion into an updated network parameter.

26. The system of claim 25, wherein the network parameter is selected from a group consisting of:

scattering parameters (S-parameters);

hybrid parameters (h-parameters);

inverse hybrid parameters (g-parameters);

transmission parameters (ABCD-parameters); and

scattering transfer parameters (T-parameters).

27. The system of claim 25, wherein the intermediate network parameter comprises impedance parameters (z-parameters).

28. The system of claim 27, wherein the value is a DC impedance of the port.

29. The system of claim 25, wherein the intermediate network parameter comprises admittance parameters (y-parameters).

30. The system of claim 29, wherein the value is a DC admittance of the port.

31. The system of claim 25, wherein the first and second portions of the intermediate network parameter are real and imaginary parts, respectively.

32. The system of claim 25, wherein the processor is configured to:

identify the first frequency based on a curve indicative of a variation of the first portion of the intermediate network parameter over the frequency range, wherein the first frequency is a frequency above which the curve becomes unflat.

33. The system of claim 25, wherein the processor is configured to:

identifying the second frequency based on an inter-plane coupling frequency, wherein the inter-plane coupling frequency is determined by at least a thickness and a conductivity of a metal plane in a multi-plane structure of the circuit.

34. The system of claim 25, wherein the processor is configured to calculate the transitional value based on at least one of:

a smoothing function and a polynomial function.

35. The system of claim 25, wherein the processor is configured to:

change the second portion of the intermediate network parameter based on Hilbert transform to ensure causality of the updated network parameter.

36. The system of claim 25, wherein the processor is configured to:

load the network model including first and second ports and first and second network parameters, each of the first and second network parameters being associated with at least one of the first and second ports, the first network parameter being defined over a first frequency range, the second network parameter being defined over a second frequency range;

convert the first network parameter into a first intermediate network parameter and convert the second network parameter into a second intermediate network parameter;

identify third and fourth frequencies in the first frequency range, the third frequency being lower than the fourth frequency;

identify fifth and sixth frequencies in the second frequency range, the fifth frequency being lower than the sixth frequency;

assign a lower frequency of the third and fifth frequencies to the first frequency; and

assign a higher frequency of the fourth and sixth frequencies to the second frequency.