B.S.T.J. Briefs: Holographic Thin Film Couplers

T H E BELL SYSTEM T E C H N I C A L J O U R N A L , SEPTEMBER 1070 (a + 2c) E,(()) + cEt (29) From eauations (5) and (7) (---~Y a + c / = t a n d/2 t a i l 0 o / 2 . (30) For most antenna designs, equation (30) is much smaller than one, the series in equations (28) and (30) are, therefore, rapidly converging, and can in principle be evaluated to any desired accuracy. It is noted that in the principal planes, these series can be related to Lommel functions of two variables3. The stimulating discussions with N. Amitay and E. R. Nagelberg are gratefully acknowledged by the author. REFERENCES 1. Cook, J. S., Elam, E. M., and Zucker, IT., " T h e Open Cassegrain A n t e n n a , " B.S.T.J., 44, No. 7 (September 1965), pp. 1255-13001. 2. Ierley, W. H., and Zucker, II., "A Stationary Phase Method for t h e Computation of t h e F a r Field of Open Cussegrain Antennas," B.S.T.J., 49, No. 3 (March 1970), pp. 431-454. 3. Gradshteyn, I. S., and Ryzhik, I. M., Tables of Integrals Series and Products, New York: Academic Press, 1965, pp. 366, 987.