monopulse secondary surveillance radar ... - Perner's Contacts

Number 5, Volume VI, December 2011Feedth‐ trough conductorPCBs1stlayer2ndlayerStriplinesDielectric bushingFig. 8 - The layered design of the vertical feeder.2.2 Horizontal feederThe horizontal feeder network comprises 27 power dividers of various types. It issegmented into three blocks: one central feeder block and two lateral ones. The central blockdiagram is shown in the Fig. 2. Consisting of six power dividers/combiners it combines threeinputs for sum, difference and SLS beam signals and distributes them to six output ports forthree central vertical feeders, for the two lateral feeder blocs and for the backfill antenna.Only the divider No. 1 is a Wilkinson type power divider, the rest ones are of the branch linetype.Verticalfeeders‐13 ‐12 ‐11 ‐10 ‐9‐8‐7‐6 ‐5‐4‐3‐2‐1‐0 +1+2 +3+4 +5+6 +7+8 +9+10 +11+12 +13Lateral feeder block ‐ leftLateral feeder block ‐ rightTo thebackfillantennaCentral feeder blockSUM Difference SLSFig. 9 - Schematic diagram of the horizontal feederThe two lateral feeder blocks are identical but mirror-oriented to provide a symmetricalexcitation of the vertical feeders (Fig. 9). The lateral feeder block is an 1/12 divider andconsists of eleven branch line power dividers. Due to a non-uniform signal amplitudedistribution at the twelve outputs the branch line dividers output power ratios have a largespan from 3 to 11 dB. Particularly the dividers with low coupling are extremely sensitive totolerances of the high impedance segments Z B (see the Fig. 7). Also the divider network isarranged in a quite nonstandard way.Bezoušek, Schejbal: Monopulse Secondary Ssurveillance radar Antenna for Air Traffic Control 27