A small slot dipole loaded with CRLH TL unit cells

A coplanar-waveguide (CPW) fed small slot dipole operating in the 2.45 GHz ISM band is presented. The slot dipole is loaded with the composite right/left-handed (CRLH) transmission line (TL) unit cells to achieve the size reduction by utilizing the zeroth-order resonance (ZOR). To realize a design that can be conveniently scaled for higher frequency applications, the CRLH TL unit cells are implemented using interdigital capacitors and inductors. The CRLH slot dipole is 28 mm (λ₀/4.4 at 2.45 GHz) in length and 57% shorter than the traditional CPW-fed slot dipole printed on the same 1.27 mm thick Rogers RO3010 ε_r = 10.2 substrate. The antenna exhibits 1.3% |S11| <; -10 dB bandwidth and 3.5 dB gain with 80% realized radiation efficiency A second slot dipole design is also carried out over a lower contrast, 1.524 mm thick Rogers RO4003C ε_r = 3.55 substrate to demonstrate the performance of the CRLH TL based miniaturization technique with various substrate materials.