2 x 2 Phased Array Consisting of Square Loop Antennas for High Gain Wide Angle Scanning With Low Grating Lobes

A 2 × 2 array antenna comprised of conventional hybrid high impedance surface-based reconfigurable square loop antennas (SLAs) as elements is presented. The SLA element has four conducting arms and each arm is fed at the middle by vertical probes, which is connected to a 50 Ω port at the bottom of antenna ground plane. Thus, the SLA element has four feeding ports and it is capable of generating five distinct radiation patterns by using a combination of its feeding ports. Depending upon which of its four ports are excited it can provide four high gain off-boresight tilted beams (8.9 dBi at θmax= 36°) in four different quadrants of the space (tilted beam mode). When all the four ports are simultaneously excited with phases of 0°, 0°, 180°, and 180°, it provides an axial beam (6.5 dBi) at boresight (axial beam mode). By combining these two modes the 2 × 2 array of SLAs can provide a scanning range of-60° to +60° in the elevation plane with high-gain beams (14-11.2 dBi)

Analysis of a Polarization Splitter With a Multilayer Filter Using a Pade-Operator-Based Power-Conserving Fourth-Order Accurate Beam-Propagation Method

A(1,1)Pade-operator-based fourth-order accurate finite-difference beam-propagation method is described for the analysis of the transverse-magnetic(TM)wave, with an emphasis on power conservation. As an application, a polarization splitter with a multilayer filter is analyzed. Reflectivities of more than 98% for the transverse-electric wave and transmissivities of more than 94% for the TM wave are obtained over a wide wavelength range of 1.1-1.65 μ

Antenna System Composed of T-Shaped Elements Coupled to an Open Radial Waveguide

An antenna system composed of an activated open radial waveguide (RadWG) and parasitic T-shaped elements is proposed as a high-gain antenna, where the radiation beam is steerable around the system axis. The T-shaped elements are proximity-coupled to the RadWG. It is found that the upper round plate for the RadWG contributes to forming a desirable beam and increasing the gain. The beam steering with a gain of greater than targeted 9 dBi in 16 azimuthal directions is obtained by changing the location of open-state T-shaped elements whose height is 0.18 wavelength. Effects on the radiation characteristics of the system parameters, including the RadWG height, upper round plate diameter, ground plane diameter, and number of open-state T-shaped elements, are also analyzed and discussed

A Three-Dimensional Multistep Horizontally Wide-Angle Beam-Propagation Method Based on the Generalized Douglas Scheme

A three-dimensional horizontally wide-angle beam-propagation method is formulated on the basis of the multistep method for higher order Pade approximants, together with the alternating-direction implicit scheme. The fourth-order accurate finite-difference formula is used to enhance the efficiency of the method. The effectiveness is demonstrated through the analyses of a tilted step-index waveguide and a multimode interference coupler

A Circularly Polarized Low-Cost Flat Panel Antenna Array With a High Impedance Surface Meta-Substrate for Satellite On-the-Move Medical IoT Applications

A 1×3 linear antenna array consisting of Quad-Arm Curl antenna with a High impedance meta-surface (QACH) is presented. We believe that it is the first linear phased array solution which can provide 360° azimuth coverage. This array has been designed to operate at L-Band (1.518 - 1.675 GHz) and generate right hand circularly polarized radiation to primarily target the Inmarsat BGAN satellite constellation. The metamaterial structure integrated into each antenna element allows a low-profile height of 17.2 mm (λ1.597/10.9). Since the curl element has wideband characteristics, the array is able to provide shared aperture functionality. The array guarantees high gain beam steering for low elevation angles (up to θ = 70° from the zenith) with an average gain of 7.96 dBic at θ = 70°. In comparison, to achieve an equivalent high gain a conventional 4×5 patch array would be required (3 elements vs 20 elements). This means that the proposed array requires 80% fewer phase shifters, amplifiers and LNAs. This translates to a crucial commercial advantage in relation to manufacturing cost. This development can lead to disruption of the existing Satcom market by lowering the barrier-to-entry for customers looking for a mass deployable, low-cost IoT on Satcom solution

Semivectorial Mode Analysis of a Rib Waveguide by an Imaginary-Distance Beam-Propagation Method Based on the Generalized Douglas Scheme

The field profile and effective index of a rib waveguide are calculated using an improved semivectorial beam-propagation method using the imaginary-distance procedure. Convergence behavior of the effective index is compared with that obtained by the conventional Crank-Nicholson scheme and with that derived from a Bierwirth-type formula, demonstrating the effectiveness of the present method. Field discontinuities at the interface between different materials are clearly displayed

Leakage Loss and Phase Variation of a Buried Directional Coupler on a Silicon Substrate

Effects of the presence of a silicon substrate on the leakage loss and phase variation of silica-based parallel waveguides are investigated using the imaginary-distance beam-propagation method. The leakage loss is evaluated as a function of the distance between the core and the substrate. Calculation shows that the loss of the directional coupler can be estimated using the single waveguide with the same cross section. It is also found that the beat length becomes longer than that without the substrate except the case where the core is extremely close to the substrate. In terms of the loss reduction, the insertion of a SiO2. film with a 1-μm thickness corresponds to an increase in the distance between the core and the substrate without the SiO2. film by about 2μm

A Three-Dimensional Horizontally Wide-Angle Noniterative Beam-Propagation Method Based on the Alternating-Direction Implicit Scheme

A three-dimensional horizontally wide-angle beampropagation method is proposed on the basis of the alternatingdirection implicit scheme, in which the Pade approximant is applied only to the horizontal direction. The present formulation reduces the splitting error to the first order without an iteration procedure. The effectiveness is demonstrated through the wide-angle propagating beam analysis of a tilted optical waveguide