THE WORK OF JAGADIS CHANDRA BOSE:
100 YEARS OF MM-WAVE RESEARCH
(last revised February 1998)
Radio Astronomy Observatory(1)
949 N. Cherry Avenue
Tucson, Arizona 85721
Based on material presented at the IEEE-MTT-S International Microwave
Symposium in Denver, CO, June 8-13, 1997; this appeared in the 1997 IEEE
MTT-S International Microwave Symposium Digest, Volume 2, ISSN 0149-645X,
pp.553-556. The full article was published in the IEEE Transactions on
Microwave Theory and Techniques, December 1997, Vol. 45, No. 12,
pp.2267-2273. This WWW version has some additional photographs, and color
images. Copyright held by the author and the IEEE.
(1)The National Radio
Astronomy Observatory is a facility of the National Science
Foundation, operated under cooperative agreement by Associated
Just one hundred years ago, J.C. Bose described to the Royal
Institution in London his research carried out in Calcutta at millimeter
wavelengths. He used waveguides, horn antennas, dielectric lenses, various
polarizers and even semiconductors at frequencies as high as 60 GHz; much
of his original equipment is still in existence, now at the Bose Institute
in Calcutta. Some concepts from his original 1897 papers have been
incorporated into a new 1.3-mm multi-beam receiver now in use on the NRAO
12 Meter Telescope.
James Clerk Maxwell's equations predicting the existence of
electromagnetic radiation propagating at the speed of light were made
public in 1865; in 1888 Hertz had demonstrated generation of
electromagnetic waves, and that their properties were similar to those of
light . Before the start of the twentieth century, many of the concepts
now familiar in microwaves had been developed [2,3]: the list includes the
cylindrical parabolic reflector, dielectric lens, microwave absorbers, the
cavity radiator, the radiating iris and the pyramidal electromagnetic
horn. Round, square and rectangular waveguides were used, with
experimental development anticipating by several years Rayleigh's 1896
theoretical solution  for waveguide modes. Many microwave components in
use were quasi-optical - a term first introduced by Oliver Lodge .
Righi in 1897 published a treatise on microwave optics .
Hertz had used a wavelength of 66 cm; other post-Hertzian pre-1900
experimenters used wavelengths well into the short cm-wave region, with
Bose in Calcutta [7,8] and Lebedew in Moscow  independently performing
experiments at wavelengths as short as 5 and 6 mm.
THE RESEARCHES OF J.C. BOSE
Jagadis Chandra Bose [10,11,12] was born in India in 1858. He received
his education first in India, until in 1880 he went to England to study
medicine at the University of London. Within a year he moved to Cambridge
to take up a scholarship to study Natural Science at Christ's College
Cambridge. One of his lecturers at Cambridge was Professor Rayleigh, who
clearly had a profound influence on his later work. In 1884 Bose was
awarded a B.A. from Cambridge, but also a B.Sc. from London University.
Bose then returned to India, taking up a post initially as officiating
professor of physics at the Presidency College in Calcutta. Following the
example of Lord Rayleigh, Jagadis Bose made extensive use of scientific
demonstrations in class; he is reported as being extraordinarily popular
and effective as a teacher. Many of his students at the Presidency College
were destined to become famous in their own right - for example S.N. Bose,
later to become well known for the Bose-Einstein statistics.
A book by Sir Oliver Lodge, "Heinrich Hertz and His
Successors," impressed Bose. In 1894, J.C. Bose converted a small
enclosure adjoining a bathroom in the Presidency College into a
laboratory. He carried out experiments involving refraction, diffraction
and polarization. To receive the radiation, he used a variety of different
junctions connected to a highly sensitive galvanometer. He plotted in
detail the voltage-current characteristics of his junctions, noting their
non-linear characteristics. He developed the use of galena crystals for
making receivers, both for short wavelength radio waves and for white and
ultraviolet light. Patent rights for their use in detecting
electromagnetic radiation were granted to him in 1904. In 1954 Pearson and
Brattain  gave priority to Bose for the use of a semi-conducting
crystal as a detector of radio waves. Sir Neville Mott, Nobel Laureate in
1977 for his own contributions to solid-state electronics, remarked 
that "J.C. Bose was at least 60 years ahead of his time" and
"In fact, he had anticipated the existence of P-type and N-type
In 1895 Bose gave his first public demonstration of electromagnetic
waves, using them to ring a bell remotely and to explode some gunpowder.
In 1896 the Daily Chronicle of England reported: "The inventor (J.C.
Bose) has transmitted signals to a distance of nearly a mile and herein
lies the first and obvious and exceedingly valuable application of this
new theoretical marvel." Popov in Russia was doing similar
experiments, but had written in December 1895 that he was still
entertaining the hope of remote signalling with radio waves. The first
successful wireless signalling experiment by Marconi on Salisbury Plain in
England was not until May 1897. The 1895 public demonstration by Bose in
Calcutta predates all these experiments. Invited by Lord Rayleigh, in 1897
Bose reported on his microwave (millimeter-wave) experiments to the Royal
Institution and other societies in England . The wavelengths he used
ranged from 2.5 cm to 5 mm. In his presentation to the Royal Institution
in January 1897 Bose speculated [see p.88 of ref.8] on the existence of
electromagnetic radiation from the sun, suggesting that either the solar
or the terrestrial atmosphere might be responsible for the lack of success
so far in detecting such radiation - solar emission was not detected until
1942, and the 1.2 cm atmospheric water vapor absorption line was
discovered during experimental radar work in 1944. Figure 1 shows J.C.
Bose at the Royal Institution in London in January 1897; Figure 2 shows a
matching diagram, with a brief description of the apparatus.
Figure 1. J.C. Bose at the Royal Institution,
London, 1897. 
By about the end of the 19th century, the interests of Bose turned away
from electromagnetic waves to response phenomena in plants; this included
studies of the effects of electromagnetic radiation on plants, a topical
field today. He retired from the Presidency College in 1915, but was
appointed Professor Emeritus. Two years later the Bose Institute was
founded. Bose was elected a Fellow of the Royal Society in 1920. He died
in 1937, a week before his 80th birthday; his ashes are in a shrine at the
Bose Institute in Calcutta.
Figure 2. Bose's apparatus demonstrated to the
Royal Institution in London in 1897 . Note the waveguide radiator on
the transmitter at left, and that the "collecting funnel" (F) is
in fact a pyramidal electromagnetic horn antenna, first used by Bose.
Bose's experiments were carried out at the Presidency College in
Calcutta, although for demonstrations he developed a compact portable
version of the equipment, including transmitter, receiver and various
microwave components. Some of his original equipment still exists, now at
the Bose Institute in Calcutta. In 1985 the author was permitted by the
Bose Institute to examine and photograph some of this original apparatus.
Figure 3 Bose's diagrams of his radiators. (a)
shows the radiator used to generated 5-mm radiation, while (b) shows the
arrangement with a lens L at the exit of the waveguide
. In some designs the mounting stems for the outer spheres could be
inclined to adjust the dimension of the spark gaps.
Figure 3 (a) shows Bose's diagram of one of his radiators, used for
generating 5-mm radiation. Oscillation is produced by sparking between 2
hollow hemispheres and the interposed sphere. There is a bead of platinum
on the inside surface of each hemisphere. For some experiments, a lens of
glass or of sulphur was used to collimate the radiation - the first
waveguide-lens antenna. The lens was designed according to the refractive
index measured by Bose at the wavelength in use. Figure 3(b) shows Bose's
drawing of such a radiator; the sparks occur between the two outer spheres
to the inner sphere, at the focal point of the lens L at
the right. Bose was able to measure the wavelength of his radiation with a
reflecting diffraction grating made of metal strips .
4(a) One of Bose's transmitter antennas (being held on the right of the
picture). Note the polarizing grid; the spark gap is just visible behind
the grid. In the background behind this antenna part of the high voltage
equipment used to generate the spark can be seen. At the left of the
picture is a receiving horn.
4(b) A closeup of the spark gaps normally mounted inside the
4(c) A complete setup showing the transmitting antenna at the left,
with the receiving antenna at right. Note the adjustment screw on top of
the receiving antenna, which is used to adjust the pressure of the
point-contact detector (see Fig. 5). In the center is a rotating table
(the "spectrometer circle" of Figure 2) on which various
microwave components (prisms, lenses, grids, polarizers etc.) may be
mounted for study. A dual-prism attenuator (see below) is shown in this
photograph. The arrangement as shown is not yet properly aligned.
Figure 4(a) is a photograph of one of his radiating antennas; part of
the spark oscillations are generated inside the overmoded circular
waveguide. A polarizing grid is built into the antenna, clearly visible at
the radiating end of the waveguide. Figure 4(b) shows a closeup of the
dual spark gaps used for the transmitter; the sparks are generated between
the 2 outer spheres and the inner sphere. Figure 4(c) shows both a
transmitting antenna (left) and the receiver (right), with a dual prism in
between set on the experimental rotating table.
Figure 5. Two of Bose's point contact detectors,
removed from the receiving antennas.
Figure 5 shows two of Bose's point contact detectors. In use, the
detector would be placed inside an overmoded waveguide receiving antenna,
very much like the transmitting antenna shown in Figure 4, and with a
matching polarizing grid.
Bose measured the I-V characteristics of his junctions; an example
characteristic curve of a "Single Point Iron Receiver" is shown
in Figure 6. The junction consisted of a sharp point of iron,
pressing against an iron surface, with pressure capable of fine
adjustment. The different curves in Figure 6 correspond to different
contact pressures. Bose noted that the junction does not obey Ohm's law,
and that there is a knee in the curve at approximately 0.45 volts; the
junction becomes most effective at detection of short wavelength radiation
when the corresponding bias voltage is applied. He made further
measurements on a variety of junctions made of different materials,
classifying the different materials into positive or negative classes of
substance. In one experiment he noted that increasing the applied voltage
to the junction actually decreased the resulting current, implying a
negative dynamic resistance .
Figure 6. The I-V characteristics measured by Bose
for a Single Point Iron Receiver. Note the similarity to modern
semiconductor junctions, with a knee voltage of about 0.4 volts.
Another of Bose's short-wavelength detectors is the spiral-spring
receiver. A sketch of a receiver used for 5-mm radiation is shown in
Figure 7; the spring pressure could be adjusted very finely in order to
attain optimum sensitivity. The sensitive surface of the 5-mm receiver was
1 by 2 cm. The device has been described recently  as a
"space-irradiated multi-contact semiconductor (using the natural
oxide of the springs)." A surviving, somewhat larger, spiral spring
receiver is shown in the photograph Figure 8. The springs are held in
place by a sheet of glass, seen to be partly broken in this example.
Figure 7. Bose's diagram of his spiral-spring
receiver used for 5-mm radiation.
Figure 8. One of Bose's free-space radiation
receivers, recently described  as a "space-irradiated
multi-contact semiconductor (using the natural oxide of the
springs)." The springs are kept in place in their tray by a sheet of
glass, seen to be partly broken in this photograph.
Figure 9 is Bose's diagram of his polarization apparatus. The
transmitter is the box at left, and a spiral spring receiver ('R') is
visible on the right. One of the polarizers used by Bose was a cut-off
metal plate grating, consisting of a book (Bradshaw's Railway Timetable,
Figure 10) with sheets of tinfoil interleaved in the pages. Bose was able
to demonstrate that even an ordinary book, without the tinfoil, is able to
produce polarization of the transmitted beam. The pages act as parallel
dielectric sheets separated by a small air gap.
Figure 9. Bose's diagram of his polarization
apparatus. Note the spiral spring receiver 'R' to the right.
Figure 10. One of Bose's polarizers was a cut-off
metal plate grating, consisting of a book (Bradshaw's Railway Timetable)
with sheets of tinfoil interleaved in the pages.
Bose experimented with samples of jute in polarizing experiments. In
one experiment, he made a twisted bundle of jute and showed that it could
be used to rotate the plane of polarization. The modern equivalent
component may be a twisted dielectric waveguide. He further used this to
construct a macroscopic molecular model as an analogy to the rotation of
polarization produced by liquids like sugar solutions. Figure 11 shows
Bose's diagram of the jute twisted-fiber polarization rotator, and Figure
12 is a photograph of a surviving twisted-jute polarizer at the Bose
Figure 11. Bose's diagram of twisted-Jute
polarization elements, used to simulate macroscopically the polarization
effect of a certain sugar solutions.
Figure 12. One of the twisted-jute polarizers used
THE DOUBLE-PRISM ATTENUATOR
Bose's investigations included measurement of refractive index of a
variety of substances. He made dielectric lenses and prisms; examples are
visible in Figures 1 and 2.
Figure 13. Bose's 1897 diagram of the double-prism
One investigation involved measurement of total internal reflection
inside a dielectric prism, and the effect of a small air gap between two
identical prisms. When the prisms are widely separated, total internal
reflection takes place and the incident radiation is reflected inside the
dielectric. When the 2 prisms touch, radiation propagates unhindered
through both prisms. By introducing a small air gap, the combination
becomes a variable attenuator to incident radiation; this is illustrated
in Bose's original diagram, shown in Figure 13. Bose investigated this
prism attenuator experimentally; his results were published in the
Proceedings of the Royal Society in November, 1897 . Schaefer and Gross
 made a theoretical study of the prism combination in 1910; the device
has since been described in standard texts.
Figure 14. One of Bose's original double-prism
attenuators, with adjustable air gap.
At the National Radio Astronomy Observatory in Tucson, Arizona a new
multiple-feed receiver, operating at a wavelength of 1.3 mm, has recently
been built and installed on the 12 Meter Telescope at Kitt Peak . The
system is an 8-feed receiver, where the local oscillator is injected into
the superconducting tunnel junction (SIS) mixers optically. With an SIS
mixer receiver the power level of the injected local oscillator is
critical; each of the 8 mixers requires independent local oscillator power
adjustment. This is achieved by adjustable prism attenuators. Figure 15
shows 4 of these 8 prism attenuators, installed on one side of the 8-feed
system; this can be compared with Figure 14, which is a photograph taken
at the Bose Institute in Calcutta in 1985, of an original prism system
built by Bose.
Figure 15. Four of the 8 double-prism attenuators
used to control local oscillator injection into the NRAO 1.3-mm 8-beam
receiver in use at the 12 Meter Telescope at Kitt Peak.
Research into the generation and detection of millimeter waves, and the
properties of substances at these wavelengths, was being undertaken in
some detail one hundred years ago, by J.C. Bose in Calcutta. Many of the
microwave components familiar today - waveguide, horn antennas, polarizers,
dielectric lenses and prisms, and even semiconductor detectors of
electromagnetic radiation - were invented and used in the last decade of
the nineteenth century. At about the end of the nineteenth century, many
of the workers in this area simply became interested in other topics.
Attention of the wireless experimenters of the time became focused on much
longer wavelengths which eventually, with the help of the then unknown
ionosphere, were able to support signalling at very much greater
Although it appears that Bose's demonstration of remote wireless
signalling has priority over Marconi, he was the first to use a
semiconductor junction to detect radio waves, and he invented various now
commonplace microwave components, outside of India he is rarely given the
deserved recognition. Further work at millimeter wavelengths was almost
nonexistent for nearly 50 years. J.C. Bose was at least this much ahead of
I wish to thank the Bose Institute in Calcutta for help with material,
and for permission in 1985 to photograph some of the original equipment of
J.C. Bose, including the photographs shown from Figures 4 to 14 in this
article. I thank Mrs. Nancy Clarke for help in preparing the manuscript.
 H. Hertz, Electric Waves. London: Macmillan and Co. Ltd.,
1893. (Reprinted by Dover.)
 John F. Ramsay, "Microwave Antenna and Waveguide Techniques
before 1900," Proc. IRE., Vol.46, No.2, pp. 405-415,
 K.L. Smith, "Victorian Microwaves," Wireless World,
pp. 93-95, September 1979.
 Lord Rayleigh, "On the passage of electric waves through
tubes, or the vibrations of dielectric cylinders," Phil. Mag.,
vol.43, pp.125-132, February 1897.
 Oliver Lodge, Signalling Across Space Without Wires. Fleet
Street, London, U.K.: "The Electrician" Printing &
Publishing Company, 1908, 4th Ed., p. 83. (First edition
published in 1894 under the title, The Work of Hertz and His
 A. Righi, L'Ottica delle Oscillazioni Elettriche. Bologna,
Italy: N. Zanichelli, 1897.
 J.C. Bose, "On the determination of the wavelength of electric
radiation by a diffraction grating," Proc. Roy. Soc., vol.
60, pp.167-178, 1897.
 J.C. Bose, Collected Physical Papers. New York, N.Y.:
Longmans, Green and Co., 1927.
 P. Lebedew, "Ueber die Dopplbrechung der Strahlen electrischer
Kraft," Annalen der Physik und Chemie, series 3, vol.56,
no.9, pp.1-17, 1895.
 Monoranjon Gupta, Jagadis Chandra Bose, A Biography.
Bombay, India: Bhavan's Book University, 1952.
 Bimalendu Mitra, Sir Jagadis Chandra Bose: A Biography for
Students. Hyderabad-Bombay-Calcutta, India: Orient Longman,Ltd.,
 B. Mitra, "Early Microwave Engineering: J. C. Bose's Physical
Researches during 1895-1900," Science and Culture, vol.50,
 Photograph from Acharya Jagadis Chandra Bose, Birth Centenary,
1858-1958. Calcutta: published by the Birth Centenary Committee,
printed by P.C. Ray, November 1958.
 G.L. Pearson, and W.H. Brattain, "History of Semiconductor
Research," Proc. IRE, 43, pp.1794-1806, 1955.
 J.C. Bose, "On the Change of Conductivity of Metallic
Particles under Cyclic Electromotive Variation," originally presented
to the British Association at Glasgow, September 1901, reproduced in Collected
Physical Papers, J.C. Bose, Ed. New York, N.Y.: Longmans, Green and
 C. Schaefer and G. Gross, "Untersuchungen ueber die
Totalreflexion," Annalen der Physik, vol 32, p.648, 1910.
 J.M. Payne & P.R. Jewell, "The Upgrade of the NRAO 8-beam
Receiver," in Multi-feed Systems for Radio Telescopes, D.T.
Emerson & J.M. Payne, Eds. San Francisco: ASP Conference Series, 1995,
vol. 75, p.144.