Lumped Element RF Filters
A lumped element RF filter is a passive device whose size across any dimension is much smaller than the operating wavelength so that there is minimal change in phase of a waveform between the input and output connections.
There are three basic lumped-element ingredients; capacitors, inductors and resistors. Ceramic chips for thermal management and resistors are also commonly used in RF Filter applications.
Lumped element designs are lower cost, smaller in footprint, and have wider bandwith characteristics than their distributed element counterparts. As these are passive devices, that do not add any energy to a signal and are reciprocal (meaning that it has a symmetric S-parameter matrix), no feature of its structure can exceed 1/10 of a wavelength at the maximum frequency of its usage.
Advantages Of Using A Lumped Element Design
- Lower Frequency
- Higher Power
- Greater Mechanical Complexity