FOR AMPLITUDE MONOPULSE SYSTEMS, conventional antennas provide only a directional mode. To offer an omnidirectional mode, such antennas will require a complicated amplitude and/or phase calibration network. At Aerospace Electronics Co., Leo G. Maloratsky has developed an L-band switched directional/omnidirectional antenna module. It comprises a four-monopole antenna, switched beamforming network (SBFN), matching network, and interface.
The switched beamforming network's switchedline 0/180-deg. phase shifter provides switching between the directional and omnidirectional modes. That network includes four 90-deg. hybrids, which are connected through four inverters. Over a 10-percent frequency range, the experimental antenna module exhibited directional gain beyond +1.0 dBi from a 90- to 100-deg. beamwidth. It exhibited return loss of less than -13.0 dB, side/ back-lobe levels below -10.0 dB, and an RMS bearing error below 2 deg. See "Switched Directional/ Omnidirectional Antenna Module for Amplitude Monopulse Systems," IEEE Antennas And Propagation Magazine, October 2009, p. 90.
About the Author
Nancy Friedrich
RF Product Marketing Manager for Aerospace Defense, Keysight Technologies
Nancy Friedrich is RF Product Marketing Manager for Aerospace Defense at Keysight Technologies. Nancy Friedrich started a career in engineering media about two decades ago with a stint editing copy and writing news for Electronic Design. A few years later, she began writing full time as technology editor at Wireless Systems Design. In 2005, Nancy was named editor-in-chief of Microwaves & RF, a position she held (along with other positions as group content head) until 2018. Nancy then moved to a position at UBM, where she was editor-in-chief of Design News and content director for tradeshows including DesignCon, ESC, and the Smart Manufacturing shows.