Reconfigurable Grounded Vector Antenna for 3-D Electromagnetic Direction-Finding Applications

Abstract

Abstract-In this letter, a reconfigurable grounded wideband antenna is proposed in view of vector sensor applications. This antenna combines two orthogonal and colocated semi-circular arrays of Vivaldi antennas mounted over a metallic support. The radiation patterns of two wideband magnetic dipoles and one wideband electric dipole can be synthesized thanks to an appropriate antenna excitation. Measurement results are in good agreement with the simulated results obtained from fullwave electromagnetic simulations. The proposed antenna exhibits stable radiation patterns over a wide impedance bandwidth of 1.69:1, a high radiation efficiency and a good isolation between the antenna input ports. This antenna is a good candidate for wideband 3D direction finding using a vector sensor.Index Terms-wideband magnetic and electric dipoles, Vivaldi antennas, vector sensor, direction-ofarrival antenna, reconfigurable antenna.

Wideband Vector Antenna for Dual-Polarized and Three-Dimensional Direction-Finding Applications

“…Moreover, the power splitter part of the feeding circuit of the Vivaldi antennas has been modified. Contrary to what is stated in [6], the input impedance of the Vivaldi antennas is about 100 Ω (and not 65 Ω) when antennas are connected within the array. Therefore, the 1:2 microstrip line power splitter used in [6], and fabricated using the Tjunction and impedance transition lines ( Fig.…”

“…Contrary to what is stated in [6], the input impedance of the Vivaldi antennas is about 100 Ω (and not 65 Ω) when antennas are connected within the array. Therefore, the 1:2 microstrip line power splitter used in [6], and fabricated using the Tjunction and impedance transition lines ( Fig. 1(f)), can be advantageously replaced by two 100 Ω parallel microstrip lines connected to the 50 Ω input port ( Fig.…”

“…1(g)). Hence, compared with [6], the new dimensions of the VA feeding circuit (reported in Table I) allows the significant enlargement of the impedance bandwidth (see Section III-A).…”

“…Following [6], the measurement of the EM field components H x , H y and E z are performed from three sets of weighting coefficients assigned to the received signals at the VA vertical ports (denoted by the acronym RPC 0, which stands for Radiation Patterns Combination 0). According to the mirror symmetry between the two feeding circuits of the 2-port vertical array ( Fig.…”

“…Many VAs have been reported over the last few years, including the active solution covering frequencies below 30 MHz [4] and the passive and dual-band solution operating at GSM frequencies [5]. Very recently, the authors proposed the first passive, wideband and radiation pattern (RP) reconfigurable VA [6]- [8], referred here to as the Two Season VA. The measured electrical characteristics of this antenna are detailed in [6], while its simulated and * Ecole Nationale de l'Aviation Civile, Université de Toulouse, F-31055 Toulouse, France (e-mail: christophe.morlaas@enac.fr).…”