A digital current controlled latching ferrite phase shifter

Abstract

B a l t i m D r e , Maryland less than model. A proposed.With ss!?EZ T h i s paper concerns the design and develop m n t of a new t y p e of latching ferrite phase shifter for use in phased array antenna system. The reporbed device differs from present multitoroid. designs which require separate switching c i r c u i t s f o r each toroidal element. In the new design, a single ferrite or garnet toroid is utilized to obtain differential phase shFpt i n n increments where n is any positive integer. This i s made possible by utilizing both major and minor hysteresis characteristics of the material. The described device is simpler in structure, more versatile, more compact, and exhibits less insertion loss than present designs.Specific designs, along with measured data, are given f o r t w o four-bit 360" C-Band (5.4 -5.9 Gc) models. A measured insertion loss of 0.5 db is obtained f o r one k.5 inch suitable switching circuit is also elements. A s indicated in the figure, a s e w ate DC current path is provided through each toroid. Rather narrow, f u l l waveguide height toroids are used in this configuration. It has been found that, this arrangement i s a good approximation t o t h e widely use twin slab, nonreciprocal phase shifter design. 8 D i g i t a l incremsnts of phase shift are obtained in these designs by switching the magnetization of the component toroids between remnent states. The details of this switching will be discussed l a t e r when the design of the new phase shifter is considered. In order t o provide a comparison with the new design, typical operating characteristics f o r a present C-band latching ferrite phase s h i f t e r are l i s t e d inTable I? A s may be seen f r o m this table, present designs offer m y desirable characteristics.How&r, in syst-&as applications, the necessity of having a separate driver for each element is expensive and adds t o btroduction the overall packaging problem. In addition, the complexity of fabrication and the necessity of increased interest being placed on including somewhat lossy dielectric separators phased array antenna systems, much effort is being extended t o improve the component phase shifters. The recent development of d i g i t a l lllatching ferritell devices has been of considerable significance1,2,3. Such phase shifters , f o r -le, have reduced switching speeds t o microsecond or submicrosecond intervals and have no need f o r bulky switching coils. This paper is concerned with the design of a new latching device wfiich obtains digital increments of phase s h i f t by using material properties exhibited in a single e b n t geometrg. Present Latching Ferrite Phase Shifters Before the specific nature of the new phase shifter is considered, it is advantageous t o rev i e w , briefly, some of the characteristics of present designs. I n these designs, four, five, o r six f e r n w e t i c toroids of various lengths are placed i n a waveguide configuration as shown i n Figure 1 . Quarter wave matching transformers are included at either end of the s...

Ferrite devices and materials

“…When the two slabs were joined by a magnetic path forming a closed toroid, as shown in Fig. 9, this device became latchable [139], [140]. Here, a magnetizing current was passed through a wire running down the center of the toroid.…”