Conical Monopole Antenna With Integrated Tunable Notch Filters

With increasing radio spectrum being allocated to wireless communications, multiband and ultrawideband systems are becoming much more prevalent. Such broadband systems are susceptible to interference, or can inadvertently radiate out-of-band emissions, so significant filtering is required at RF front-ends. With this motivation, a broadband conical monopole antenna with integrated tunable notch cavity filters is presented. The antenna is a complex structure but it can be conveniently realized with lightweight perforated alloy surfaces using 3-D printing. This coax-fed antenna is demonstrated to maintain its omnidirectional azimuthal pattern with a very wide notch-tuning range, resulting in a versatile broadband antenna.