A Tunable and Electrically Small Antenna for Compact GNSS Receivers

The electronic receivers of global navigation satellite systems (GNSSs) are implemented in various handheld electronic devices such as laptops, smartphones, and smartwatches; therefore, their dimensions are of critical importance. Achieving a GNSS terminal of a small size is difficult due to its relatively low operational frequency (L-band), which is equivalent to a wavelength of approximately 24 cm. As an efficient half-wavelength antenna is too large for compact devices, in this paper, an electrically small antenna (ESA) for GNSS terminals is presented. The antenna was miniaturized by using a dielectric block with relatively high permittivity, making some parts virtual, and optimizing its geometry. The operational frequency of the ESA is tunable by means of metallic rods of variable heights inserted into a cylindrical cavity drilled inside the dielectric block. The results confirm the feasibility of the concept and the usability of the ESA for compact GNSS terminals.