Dr. Julius Herman, 69, who retired in 1970 after four years as scientific adviser to the director of the Naval Security Group, died of a heart ailment May 15 at the Washington Hospital Center.

Dr. Herman was an authority in communications technology, including electromagnetics and antennas, and had done extensive work in the theory of loop radiation.

He began his government career as an electrical engineer with the Army Signal Corps in 1942. Later during World War II he saw active duty with the Army in the Pacific, where he earned the Bronze Star Medal.

After spending five years with the Naval Ordnance Laboratory, he joined the old Diamond Ordnance Fuze Labs in Washington as an electronics scientist, where he worked until 1960.

After working for Republic Aviation in New York and General Precision Labs in New Jersey, he returned to Washington in 1965.

He spent a year on the staff of the technical analysis office of Hughes Aircraft here before joining the Naval Security Group in 1966.

Dr. Herman was a native of New York City and a graduate of the old City College of New York. He earned a doctoral degree in electrical engineering at the University of Maryland.

He was a member of the Institute of Electrical & Electronic Engineers.

Dr. Herman was codirector of Help End Energy Dependence (HEED) and was a member of the Zionist Organization of America.

He was a resident of Silver Spring.

Survivors include his wife, Lea G., of Silver Spring; a son, Dr. David E. of Columbia, Md.; a daughter, Dr. Rochelle Herman of Rockville; and two sisters, both of New York City.