Compact power dividers with filtering capability for ground penetrating radar applications

In this letter, it is demonstrated that wide-band power dividers with filtering capability can be implemented by adding an inductive transformer to the output stage of a band-pass filter. By this means, the load of the device (corresponding to the parallel connection of the two terminated output ports) can be driven to the required value to achieve input matching, and the filtering and splitting action are combined in a single device. Two proof-of-concept demonstrators, implemented in microstrip technology using complementary split-ring resonators are presented. These devices are useful to reduce the size of the microwave front-end of frequency-modulated continuous-wave ground penetrating radars operating at the L-band, as they are very compact. Moreover, the proposed devices provide the necessary bandwidth to achieve significant in-depth resolution, and the necessary stop-band rejection to suppress the harmonics of the modulated radar signal. © 2012 Wiley Periodicals, Inc.