Compact ultra-wideband filtering antennas on low temperature co-fired ceramic substrate

In this paper, co-designs of filters and ultra-wideband (UWB) antennas are presented to reduce the overall component size on a low temperature co-fired ceramic (LTCC) substrate. In the co-design, the mutual coupling between an antenna and a filter is taken into account. Thus, in the final design, the filter becomes part of the antenna. The resulting compact component, a filtering antenna, behaves as an antenna with desired radiation performance and as a filter that suppresses undesired signals, simultaneously. Two filtering antennas are designed. The first is for the 3.1-4.85 GHz lower UWB band and the second with a notched band around the 5 GHz wireless local area network band for the full UWB band of 3.1-10.6 GHz. The proposed antennas show monopole-like radiation patterns in the desired bands and high out-of-band rejection.