RFnegative

RFnegative is a nonstandard term that appears in some radiofrequency (RF) engineering discussions and research. It does not designate a single agreed-upon property; instead, it is used informally to describe phenomena in which the RF response is, in some sense, negated or inverted relative to a reference condition. Common interpretations include: phase inversion of an RF signal with respect to a reference channel, yielding a 180-degree phase difference; negative impedance or negative-resistance behavior observed in certain circuit blocks or materials over a band; and negative-index, or backward-wave, propagation in metamaterials engineered to operate at RF frequencies, which is sometimes described loosely as RFnegative.

In practice, the term may appear in design notes, simulations, or experimental reports to flag a counterintuitive or inverse response. Applications discussed in the literature include metamaterial-based antennas, compact phase shifters, or cancellation schemes that exploit inverted phase or impedance characteristics. However, RFnegative is not a standardized term, and its meaning varies with author and context.

Because of its ambiguity, readers should consult the original source for the exact definition and scope when encountering RFnegative. Related concepts include negative refractive index, left-handed materials, metamaterials, negative impedance converters, and phase reversal.