Electrically small circularly polarized antenna using vialess CRLH-TL and fractals for L-band mobile satellite applications

This paper explains the design and development of an electrically small (ka = 0.59) circularly polarized (CP) antenna based on vialess composite right/left-handed (CRLH) transmission line (TL) and third-iterative fractals (TIF) applicable for 1.637 GHz L-band mobile satellite applications. The idea behind the CP antenna originates from the combination of curved meander line inductor on the top side of the substrate back coupled with TIF in backside of the substrate. The loading of TIF provides an increased level of cross polarization by adjusting the dimensions of TIF which is almost equal to the main polarization level of original CRLH-TL loaded antenna on the top side of the substrate. Due to this, the antenna can generate two orthogonally polarized modes for supporting CP radiation with excellent miniaturization and improved gain. The overall dimensions of the proposed antenna are 22 x 27 x 1.27 mm with radiating element size including the ground plane are 0.11 lambda(0) x 0.14 lambda(0) x 0.006 lambda(0) at 1.635 GHz. The proposed antenna can provide excellent miniaturization of 68.51% compared with the conventional monopole antenna with improved radiation performance. The antenna provides an acceptable impedance bandwidth of 0.73%, improved gain of 1.79 dBi without using complex vias, excellent miniaturization, and low profile (0.006 lambda(0)) compared to existing similar type of antennas in the literature.