Investigation of use of superimposed surface wave modes.

A novel method of achieving a matched radiating element in a phased array antenna over a wide scan angle has been investigated. This method has been applied in the design of an experimental linear array of 41 elements. Each radiating element consists of an open-ended waveguide driven by an end-on coaxial transition in conjunction with offset posts for the appropriate excitation of the two lowest order modes. The measured input VSWR over a 55 degree scan angle was less than 1.5 on this experimental linear array. This result agreed fairly well with the predicted value. In addition, no degradation on the array pattern due to edge effect was observed on the experimental array with all the elements matched over the 55 degrees scan range. (Author).Prepared for Air Force Cambridge Research Laboratories, Office of Aerospace Research, United States Air Force, Bedford, Massachusetts.Contract No,. AF19(628)-4984; Project No. 4600; Task No. 460002."25 February 1967."Includes bibliographical references (pages B1-2)A novel method of achieving a matched radiating element in a phased array antenna over a wide scan angle has been investigated. This method has been applied in the design of an experimental linear array of 41 elements. Each radiating element consists of an open-ended waveguide driven by an end-on coaxial transition in conjunction with offset posts for the appropriate excitation of the two lowest order modes. The measured input VSWR over a 55 degree scan angle was less than 1.5 on this experimental linear array. This result agreed fairly well with the predicted value. In addition, no degradation on the array pattern due to edge effect was observed on the experimental array with all the elements matched over the 55 degrees scan range. (Author).Mode of access: Internet