Design of Nonuniformly Spaced Antenna Arrays Using Orthogonal Coefficients Equating Method

Orthogonal Coefficients Equating (OCE) method as an analytic method is proposed to synthesize nonuniformly spaced antenna arrays to have array factors nearly equal to that of a previously designed uniformly spaced antenna arrays. In this method, the orthogonal coefficients of array factors of nonuniformly space array are equated to those of uniformly space array. To this end, three orthogonal functions including Chebyshev polynomials, Legendre polynomials and exponential functions are discussed. Some examples are brought to verify the performance of the OCE method for all three orthogonal functions

Multifrequency Wilkinson power divider using microstrip nonuniform transmission lines

A new idea is proposed to modify the conventional Wilkinson power dividers to operate at two or several desired frequencies. The proposed structure contains two Microstrip Nonuniform Transmission Lines (MNTLs) instead of two uniform ones with nearly the same length at the minimum frequency. The strip width of MNTLs is considered variable and is written as a truncated Fourier series. Three nonuniform power dividers are designed and one of them operating at frequencies 1.0, 2.8, and 4.5 GHz is fabricated and measured. The measured results of the fabricated diplexer have a good agreement with the theoretical results. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

Subwavelength focusing and resolution with hyperbolic transmission line metamaterial

We show the potential of using two dimensional hyperbolic metamaterials (HMs) made of microstrip transmission line (TL) grids loaded by lumped components for achieving subwavelength focusing and resolution at microwave frequencies. The designed planar HM exhibits a very flat wavevector-dispersion diagram over a wide frequency range, signature of the so-called canalization regime. The canalization regime allows us to transfer the field profile of a single point source at the interface through the HM, with full width half maximum of λg / 69, where λg is the guided wavelength in the isotropic TL grid at 200 MHz. We also report the ability to resolve two point sources with subwavelength distance of λg / 15. © 2013 IEEE

Nonsingular Green’s Functions for Multi-Layer Homogeneous Microstrip Lines

In this article, three new green's functions are presented for a narrow strip line (not a thin wire) inside or on a homogeneous dielectric, supposing quasi-TEM dominant mode. These functions have no singularity in contrast to so far presented ones, so that they can be used easily to determine the capacitance matrix of multi-layer and single-layer homogeneous coupled microstrip lines. To obtain the green’s functions, the Laplace’s equation is solved analytically in Fourier integral or Fourier series expressions, taking into account the boundary conditions including the narrow strip. The validity and accuracy of three presented green’s functions are verified by some examples

Analysis of Planar Diodes in Temperature Limited Region

The ideal analysis of planar diodes in Temperature Limited Region is presented. Two types of relations are obtained for electric potential and electric field distributions one accurate but implicit and the other almost accurate but explicit