ABSTRACTS OF TECHNICAL ARTICLES 373 



Microwave Antenna Measurements} C. C. Cutler, A. P. King and W. E. 

 KocK. A description is given of the techniques involved in measuring the 

 properties of microwave antennas. The measuring methods which are 

 pecuhar to these frequencies are discussed, and include the measurement of 

 gain, beam width, minor lobes, wide-angle radiation, mutual coupHng be- 

 tween antennas, phase, and polarization. The requirements of the antenna 

 testing site are taken up, and components of a complete measuring system 

 are briefly described. 



Microwave Converters} C. F. Edwards. Microwave converters using 

 point-contact silicon rectifiers as the nonlinear element are discussed, with 

 particular emphasis on the design of the networks connecting the rectifier 

 to the input and output terminals. Several converters which have been 

 developed during recent years for use at wavelengths between 1 and 30 centi- 

 meters are described, and some of the effects of the impedance-versus-fre- 

 quency characteristics of the networks on the converter performance are 

 discussed. 



Recent Developments in Relays:"^ Glass-Enclosed Reed Relay, W. B. Ell wood; 

 Mercury Contact Relays, J. T. L. Brown and C. E. Pollard. Relays which 

 combine high-speed and great uniformity of performance over long periods 

 of time are required for some uses in the telephone plant. The relays de- 

 scribed possess these qualities to an unusual degree. Detailed description 

 is limited to two types, each typical of a generic family in which the prin- 

 ciples involved apply to all. 



These relays are based on the philosophy that a motor element (any device 

 for conversion of electromagnetic to mechanical energy), which is efficient 

 and magnetically and elastically stable and operates contacts sealed in a 

 proper atmosphere free from dirt and film, will give reliable performance if 

 the contact load is engineered to the capacity of the contact. The relays 

 require no maintenance beyond unit replacement, for there is no possibility 

 of a change in adjustment after assembly is completed. 



In one form the contact is provided for by metal in sohd form, while in the 

 other a mercury film supported on solid metal surfaces provides the con- 

 tacting medium. The mercury at the contacting surfaces is replenished 

 continuously through a capillary path from a mercury reservoir below the 

 contact. 



An Adjustable Wave-Guide Phase Changer} A. Gardner Fox. A very 



interesting and useful component of the wave-guide art is the differential 



phase-shift section, wherein dominant waves of one polarization are caused 



to travel through a section of wave guide at a different velocity than waves 



"> Proc. I. R. E., December 1947. 

 6 Proc. I. R. E., November 1947. 

 ^ Elec. Engg., November 1947. 

 8 Proc. I. R. E., December 1947. 



