A Switchable Linear to Circular Polarization Converter Using PIN Diodes

Abstract

In this paper, we present a method to design a switchable polarizer using p-i-n diodes. An antenna-filterantenna architecture with four metal layers (receiving and transmitting radiating elements, ground plane, and bias lines) is implemented to convert an impinging linearly-polarized electromagnetic wave to a circularly-polarized one. Furthermore, by controlling opportunely the bias current flowing on the two pi-n diodes flip chipped on the transmitting radiating element, the transmission wave can be switched to either left-handed circular polarization (LHCP) or right-handed circular polarization (RHCP). Full-wave electromagnetic simulations of a single element show a transmission loss < 0.8 dB for both polarization (LHCP/RHCP) and 180° phase difference in the frequency band (27 -31 GHz).

Multifunctional Electronically Reconfigurable Electromagnetic Surfaces for Ka-Band Antennas

“…The design at Ka-band and preliminary results of the reconfigurable LP-to-CP converter, of period p, shown in Fig. 1b, have been reported in [5]. The UC comprises 4 metal layers.…”

“…The asymmetric excitation and the shape of O-slot makes the top patch radiate a CP, when the two diodes are biased in opposite states. The handedness of the CP can be switched by swapping the bias states of the diodes, which reverses the current flow on the patch [5].…”

“…They are thus suitable for diverse applications, e.g. polarization manipulation, holography, and energy-efficient beam-forming [1]- [5]. Though a few EM surfaces performing multiple functions have been proposed [1], [2], the research on them is at an early stage.…”

“…This paper presents novel multifunctional Ka-band cells and surfaces using p-i-n diodes, based on the designs in [3]- [5]. First, a linearly-polarized (LP) transmitting (Tx) and reflecting UC is discussed.…”

“…It realizes a uniform 2-bit and 1-bit phase quantization in transmission and reflection, respectively, ensuring a finer resolution with respect to state-of-the-art switch-based designs [2]. This UC is co-optimized with the LP-to-circular polarization (CP) converter reported in [5]. In this way, a 2-bit UC radiating either a left-handed (LH) or right-handed (RH) CP is obtained.…”