The entries that follow purposely exclude the high-end / expensive tools that designers are probably already familiar with.

(Under Construction)

**General Calculation**

Many people use MATLAB and C++ as their computational tools of choice, but there are quite a few alternatives available, many in open-source format. Here are a few leads to get the curious going:

Python with NumPy / Scipy

Python with matplotlib

Freemat (high degree of compatibility with MATLAB)

Maxsima

Scilab

PTOLEMY out of UC Berkeley

A couple of more extensive discussions about alternatives to MATLAB can also be found here and here.

Computation times can vary dramatically between software. As others have noted, most languages have a quirk or two about them and seemingly simple calculations can on occasion take forever. A skilled user can often navigate around these issues, so any benchmark comparisons like the ones that follow should be taken with a grain of salt.

For an example, we will consider is a simple case of solving the 2D Laplace equation using an iterative finite difference scheme (four point averaging, Gauss-Seidel or Gauss-Jordan). The formal specification of the problem is as follows. We are required to solve for some unknown function u(x,y) such that ∇^{2}u = 0 with a boundary condition specified. For convenience the domain of interest is considered to be a rectangle and the boundary values at the sides of this rectangle are given.

It can be shown that this problem can be solved using a simple four point averaging scheme as follows. Discretise the domain into an (nx x ny) grid of points. Then the function u can be represented as a 2 dimensional array – u(nx, ny). The values of u along the sides of the rectangle are given. The solution can be obtained by iterating in the following manner.

for i in range(1, nx-1):

for j in range(1, ny-1):

u[i,j] = ((u[i-1, j] + u[i+1, j])*dy**2 + (u[i, j-1] + u[i, j+1])*dx**2)/(2.0*dx**2 + dy**2))

The rather remarkable computation times that were reported follow:

Solution Method | Execution Time (sec) |
---|---|

Python (estimate) | 1500.0 |

Python + Psyco (estimate) | 1138.0 |

Python + NumPy Expression | 29.3 |

Pryrex | 2.5 |

MATLAB (estimate) | 29.0 |

Octave (estimate) | 60.0 |

Pure C++ | 2.16 |

**Circuit Analysis & Simulation**

LTspice IV (by Linear Technology) A remarkably capable analysis tool that is truly free.

Mesh Electronic Circuit Analysis 2.0

Top Spice (I personally own and use this product and am pleased with it.)

AppCad for RF & Microwave circuit analysis. Originally developed by the staff of Hewlett-Packard

**Filter Design**

**RF & Microwave Filter Design**

FilPro- with a rather remarkable software manual

**Digital Filter Design**

**Frequency Planning**

**Mixer Spurious Performance**

**Antennas**

Electromagnetic modeling tools at Clemson University

**Wire Antennas**

**Microstrip Antennas**

**Other**

**Other Sites with Listings**