GC4701

A diode limiter is a power-sensitive variable attenuator that uses the non-linear properties of the diode to pro- vide an impedance mismatch when sufficient amounts of RF power are incident on the device. The output power is reduced to a level that will not overdrive a re- ceiver, burn out a mixer, etc. For varying input power levelsinexcessofthediodesthresholdlevel, thelimiters output power tends to remain constant.

A passive limiter is one in which the limiter diodes are turnedonbytheRFsignalitself. Anactivelimiterisone inwhichthelimiterdiodesareturnedonprimarilybyan externalbiascurrenttypicallysuppliedbyaSchottkyde- tector diode which senses the incident signal.

Since limiter diodes are not designed to dissipate large amounts of power, the limiter must reflect or divert the excess incident power back to the source or to another load (i.e. via a circulator, hybrid coupler, etc.).

Limiter diodes may be used in wave guides, coax, mi- crostrip, stripline or other media. Single or cascaded devices may be used, depending on power levels.

The GC4700 series diodes are specially processed PIN diodes designed for use in passive or active limiters at frequencies through Ku band. Twelve categories of devices are offered for flexibility in design of low (lower Vb, fastest turn-on time), me- dium and high (highest Vb, slowest turn-on time) power limiters.