Wizards of Electromagnetism

A Defective Ground Structure (DGS) is an intentionally designed defect on a ground plan, which creates additional effective inductance and capacitance.  This technique can be used to design microstrip lines with desired characteristics such as higher impedance, band rejection and slow-wave characteristics, while significantly reducing the footprint of the microstrip structure.  DGS structures are used in RF/microwave components (filters, dividers, amplifiers and high-speed digital designs.

However, designing DGS structures can be tricky.  Design tools typically don’t include closed-form DGS circuit models, so EM simulation is required to analyze and optimize these structures to meet the design goals.

Both time-domain and frequency-domain EM simulation can be used to simulate DGS structures.  Time-domain techniques, such as Finite Difference Time Domain (FDTD), can provide insightful TDR results.  Frequency-domain techniques, such as Finite Element Method (FEM), can very quickly find the resonant frequencies.  Both techniques provide very accurate results compared to measurements.

Read the full details in our presentation EM Insights Series – Episode 12 – Simulation of Defected Ground Structures

See the full series at EM Insights Series