Reconfigurable Reflectarray Antenna: A Comparison between Design Using PIN Diodes and Liquid Crystals

This work presents the design and analysis of active reflectarray antennas with slot embedded patch element configurations within an X -band frequency range. Two active reflectarray design technologies have been proposed by digital frequency switching using PIN diodes and analogue frequency tuning using liquid crystal-based substrates. A waveguide simulator has been used to perform scattering parameter measurements in order to practically compare the performance of reflectarray designed based on the two active design technologies. PIN diode-based active reflectarray unit cell design is shown to offer a frequency tunability of 0.36 GHz with a dynamic phase range of 226°. On the other hand, liquid crystal-based design provided slightly lower frequency tunability of 0.20 GHz with a dynamic phase range of 124°. Moreover, the higher reflection loss and slow frequency tuning are demonstrated to be the disadvantages of liquid crystal-based designs as compared to PIN diode-based active reflectarray designs.

Multiband and Low-Profile Frequency Reconfigurable Microstrip Patch Antenna Design Using Single PIN diode for WiFi/GPS applications

The novel and simple approach for achieving frequency tunability is presented. The frequency tunability is achieved using a single PIN diode. PIN diode located on the upper side of the structure to reduces the biasing complexity. The superstrate structure along with the corner truncation helps for enhancing the performance parameters, as well the location of feed and slot of the patch is varied for locating best performing points. This design provides the multiband frequency tunability behavior with the maximum frequency tunability of 100 MHz. The design provides the minimum reflectance coefficient of -22.56 dB, the directivity of 6.98 dB, the total gain of 3.683 dB, normalized directivity of 88 0 using the low profile (FR-4) substrate which helps for the cost reduction and mass production. The simulation is carried out using the HFSS tool. The fabrication of the proposed design is also presented. This design suitable for Wifi, GPS, and many more wireless communication applications.

A Novel Dual-Band Conformal Surface Plasmons Waveguide With Tunable Frequency Response In Large-scale

A novel dual-band conformal surface plasmons (CSPs) waveguide is designed and well studied in this paper. In earlier researches, we have recognized that electromagnetic field of CSPs waveguide are always confined to a sub-wavelength area and have a strong potential to be applied in devices designing. However, almost all of the earlier CSP structures is mainly focus on the fundamental mode characteristics with only single resonance frequency. Here we propose a innovative dual inverted-L structure with excellent performance not only on the fundamental mode but also on a new upper mode. This structure operates in microwave frequencies regime and shows outstanding frequency tunability characteristic. Being different from frequency characteristics in the earlier CSP waveguides which always used to be designed single-frequency device, dual-frequency tunability can be obtained via the dual L-type bending branch of the periodical CSP structure. In present paper, we also realize a tunable dual-frequency filter by changing the scaling factor of inverted-L stubs.

Numerical Study of a Reconfigurable Multiband Microwave Photonic Filter Using a Tunable Fabry-Perot Filter

Microwave photonic filters (MPFs) with the capabilities of bandwidth reconfigurability and frequency tunability in the GHz range are of great interest in high-speed communications systems. In this paper, we propose a new reconfigurable multiband microwave photonic filter (MPF) using a tunable Fabry–Perot Filter (FPF). It is demonstrated by numerical simulations that the modification of the intermodal separation (δλ) of a multimode laser diode (MLD) by tunable FPF allows for the reconfigurable multi-passband of the MPF. Our simulation results show that our new filter system is promising to communications systems.

Controllable excitation of multiple spin wave bullet modes in a spin Hall nano-oscillator based on [Ni/Co]/Pt multilayers

Spin-torque nano-oscillators are promising candidates for many radio frequency and magnon-based nanodevices due to broad frequency tunability, easy fabrication and high durability. To explore the tunability, we choose a [Ni/Co]/Pt-based...

Development of a Pin Diode-Based Beam-Switching Single-Layer Reflectarray Antenna

This paper presents a practical demonstration for the design and development of a switchable planar reflectarray using PIN diodes in the X-band frequency range. Waveguide scattering parameter measurements for the unit cells and far-field measurements of the periodic reflectarrays have been carried out to verify the predicted results. Reflectarray unit cell measurements demonstrated a frequency tunability of 0.36 GHz with a dynamic phase range of 226°. On the other hand, the designed 6 × 6 periodic reflectarray has been shown to achieve beam switching from +6° to −6° with different switching states of PIN diodes. This type of beam switching can be used in satellite communication for specific region coverage.