Affiliated with the
Communication & Space
Sciences Laboratory

Novel Electromagnetic Metamaterials

Negative Impedance Elements

Members of CEARL have been investigating the use of active loads to control the backscattering properties of PEC wire structures. In particular, a class of active loads known as negative impedance converters in the form of single elements, both real and reactive, as well as simple networks are considered.

Dipole Backscatter with Series Negative LC Load

We have found that negative capacitance and negative inductance loading applied separately, have complementary effects shifting the resonant frequency and altering the Q but also make no change in the system gain-bandwidth product. However, applied in combination as a series connected negative LC load leaves the resonant frequency and cross-section magnitude largely unaffected but significantly increases bandwidth.

 

..: References :..

1-) The Backscattering Characteristics of Wires Actively Loaded with Negative Impedance Elements
by B. R. Long and D. H. Werner
2001 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting. Boston, Massachusetts, July 8-13
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