Negative impedance converter-based impedance matching technique to achieve mutl-feed multi-band antennas

摘要

An impedance matching network for an electrically-small antenna 1 comprises branches 20,7,8 coupled between the antenna and respective ports 6,4,5.Some branches 7,8 comprise a pre-matching impedance transformer 10,11, a negative impedance converter (NIC) 16,17 and a post-matching network 13,14 connected in series. Some other branches, such as branch 20,may be purely passive. The branches may provide impedance matching in different LTE and GPS/GNSS frequency bands. The pre-matching impedance transforming networks 10,11 provide band selection and yield a suitable impedance level over the operating band so that the NICs 16,17 can more readily cancel the imaginary part of the transformed impedance of the antenna 1.