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Filter design using fractral geometry (Sierpinski resonator with a microstrip feed)

% Clear and initialize close all; clc; % Add OpenEMS and CSXCAD paths addpath('C:\openEMS\matlab'); addpath('C:\openEMS\CSXCAD\matlab'); % Constants c0 = 299792458;  % Speed of light in vacuum [m/s] unit = 1e-3;     % millimeter %% Adjustable Parameters iter = 2;                    % Sierpinski depth sideLength = 30;            % Triangle side [mm] substrate_thickness = 1.6;  % mm eps_r = 4.4;                % Dielectric constant of FR4 f_start = 1e9;              % Simulation start frequency f_stop = 10e9;              % Simulation stop frequency res = 30;                   % Mesh resolution factor %% Calculate microstrip width for 50 Ohm Z0 = 50; h = substrate_thickness; er = eps_r; if Z0 <= 60     W = (8 * h) *...
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Fractral theory in filter design

Fractals are geometric figures characterized by self-similarity and complexity across scales. Common examples are Koch curve, Sierpinski gasket and Minkowski island. These structures are recursive and can occupy a large effective electrical length in a compact physical space.Fractals are useful  in microstrip and planar filter design  because, Fractal geometries allow for longer current paths in small areas, reducing the overall footprint of filters.Due to their multi-scale nature, fractal filters can inherently support multiple resonances, useful for designing multi-band filters (e.g., WiFi + LTE).Also, the Recursive and distributed features of fractrals  lead to enhanced coupling and broader passbands. The main advanmtages of fractal based designs are  Size reduction, Improved performance at multiple frequencies, Better stopband suppression and Design flexibility.  The structure is built atop an FR4 substrate with a relative permittivity of 4.4 and ...
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  Analyzing the provided openEMS code for errors or issues Okay, let's tackle this openEMS code correction. First, I'll go through the user's code step by step to identify possible issues Starting with the simulation parameters. The frequency range is 2-4 GHz, which makes sense for through-wall applications. The mesh resolution is set to lambda/30, which should be fine, but maybe check if it's too coarse for the PBG structure Looking at the FDTD setup, they're using PML boundaries on all sides. For antenna simulations, sometimes it's better to use MUR absorbing boundaries instead of PML, especially if the structure is radiating into free space. But PML might be okay here. The Gaussian excitation is centered at 3 GHz, which is correct The substrate is FR4 with a thickness of 1.6 mm. The code adds a box for the substrate, but the dimensions are 100x100 mm. That seems a bit large. Maybe reduce it to save computation time, but ensure it's larger than the PBG and...
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