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HEWLETT-PACKARD
JOURNAL
T E C H N I C A L I N F O R M A T I O N F R O M T H E - d p - L A B O R A T O R I E !
Vol. 16, No. 4
UBLISHED BY THE HEWLETT-PACKARD COMPANY, 1501 PAGE MILL ROAD, PALO ALTO, CALIFORNIA DECEMBER, 1964
Microwave Harmonic Generation
and Nanosecond Pulse Generation
with the Step-Recovery Diode
-hp-'s affiliate, hp associates, contributing to the advance of the
was established four years ago to art in optoelectronics and solid-state
perform research, development and microwave devices.
manufacturing in the semiconductor One of hpa's developments having
field. After beginning with the devel general interest to design engineers
is the Step Recovery Diode. This de
opment of specialized silicon, germa
vice has made possible advances in
nium, and gallium arsenide diodes, fast pulse work and is unique as an
hpa has gone on to achieve industry efficient generator of high-order har
leadership in metal-on-semiconduc- monics. These capabilities are de
tor ("hot carrier") technology and is scribed in the following article.
Fig. 1. Oscillogram showing portion of
a harmonic spectrum available from a /\NY p-n junction semiconductor diode can be made to
typical Step Recovery Diode. Harmon
ics generated by 50 Me driving signal conduct heavily in the reverse direction for a brief time
(Fig. 5) and singly detected by square- immediately following forward conduction. This mo
law detector.
mentarily augmented reverse conductivity results from
the presence of stored minority carriers which had
been injected and stored during forward conduction.
In the past such reverse storage-conduction has been
considered as detrimental in many applications, and
so-called "fast-recovery diodes" were developed to
reduce it.
Recently, hp associates developed a very different
class of semiconductor diodes. These were designed to
enhance storage and to achieve an abrupt transition
Fig. 2. Oscillogram of very fast step from reverse storage-conduction to cutoff. The abrupt
(300 picoseconds) formed using Step
Recovery Diode to steepen pulse-front ness of this transition is such that it can be used to
as described in text. Pulse amplitude
here is 4 volts. switch tens of volts or hundreds of milliamperes in less
than a nanosecond. Such a combination of switching
speed and power-handling range is not possible with
any other existing device. It enables the diodes to gen
erate milliwatts of power at X-band or to provide fast
pulses at amplitudes of tens of volts across 50 ohms.
As power generators, the diodes will generate high-
order harmonics in the microwave region with greater
efficiency and simplicity than is possible by any other
Fig. 3. Step Recovery Diodes in glass means. In pulse work, the diodes will generate frac
and ceramic packages. Ceramic pack
age is designed to be especially useful tional-nanosecond pulses in which amplitude and tim
u-ith coaxial structures but can also be ing can be freely controlled, as described in the latter
used in other ways as in Fig. 8.
P R I N T E D I N U S A .