1-57
Figure 1-71B.—Hybrid ring with wavelength measurements.
The hybrid ring is used primarily in high-powered radar and communications systems to perform
two functions. During the transmit period, the hybrid ring couples microwave energy from the transmitter
to the antenna and allows no energy to reach the receiver. During the receive cycle, the hybrid ring
couples energy from the antenna to the receiver and allows no energy to reach the transmitter. Any device
that performs both of these functions is called a DUPLEXER. A duplexer permits a system to use the
same antenna for both transmitting and receiving. Since the only common application of the hybrid ring is
as a duplexer, the details of hybrid ring operation will be explained in later NEETS modules concerning
duplexers.
Q-53. What are the two basic types of T junctions?
Q-54. Why is the H-type T junction so named?
Q-55. The magic-T is composed of what two basic types of T junctions?
Q-56. What are the primary disadvantages of the magic-T?
Q-57. What type of junctions are formed where the arms of a hybrid ring meet the main ring?
Q-58. Hybrid rings are used primarily for what purpose?
Ferrite Devices
A FERRITE is a device that is composed of material that causes it to have useful magnetic properties
and, at the same time, high resistance to current flow. The primary material used in the construction of
ferrites is normally a compound of iron oxide with impurities of other oxides added. The compound of
iron oxide retains the properties of the ferromagnetic atoms, and the impurities of the other oxides
increase the resistance to current flow. This combination of properties is not found in conventional
magnetic materials. Iron, for example, has good magnetic properties but a relatively low resistance to
current flow. The low resistance causes eddy currents and significant power losses at high frequencies
(You may want to review NEETS, Module 2, Introduction to Alternating Current and Transformers,
Chapter 5). Ferrites, on the other hand, have sufficient resistance to be classified as semiconductors.
