Mode‐matching analysis of H‐plane ferrite‐loaded rectangular waveguide discontinuities

The full set of eigenmodes existing in a ferrite‐slab‐loaded rectangular waveguide is first obtained and then used to compute the scattering matrix of a junction between an air‐filled rectangular waveguide and an H‐plane ferrite‐slab‐loaded rectangular waveguide by using the mode‐matching method. Numerical results for the scattering parameters of the H‐plane waveguide discontinuity are compared to experimental data and those obtained by Ansoft's HFSS. Good agreement is observed. To demonstrate the usefulness of this structure, a computer‐optimized 90° nonreciprocal phase shifter is designed using an H‐plane ferrite‐slab‐loaded waveguide. With only one‐step impedance matching sections at both ends of the ferrite slab, a compact design is achieved to have 2° phase error and less than ?30 dB return loss over about 5% bandwidth. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 259–268, 2003.     

Parallel electromagnetic modeling of 3D microstrip discontinuities using FEM and PML

An approach is developed for 3D microstrip discontinuities using the finite element method (FEM) and the perfectly matched layers (PML). It is shown that iterative solvers are not suitable for this problem since the matrix equations from the PML‐used FEM modeling are rather ill‐conditioned and lead to a very slow or nonconvergent result. A newly developed package SuperLU of the sparse LU decomposition solver is incorporated into our developed approach running on a PC‐based parallel platform. Various implementation techniques are detailed. Numerical experiments clearly show that the developed approach is reliable, efficient, and suitable for modeling 3D microstrip discontinuities. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 38–47, 2001     

Full‐wave analysis of azimuthally magnetized ferrite‐loaded circular structures using the one‐dimensional finite difference frequency domain method

Full‐wave analysis of circular guiding structures completely filled with ferrite by using the finite difference frequency domain method is presented. The ferrite is assumed to be azimuthally magnetized to remanence. Emphasis is placed on the TE_0m modes that are rotationally symmetric. These modes exhibit nonreciprocal behavior that could be exploited to build phase shifters and microwave isolators. Dispersion diagrams for these modes are given for both forward and reverse waves, and the effect of various ferrite parameters is studied. It is shown that the dispersion diagram may exhibit a region of negative slope, which gives rise to backward wave. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Half mode substrate‐integrated waveguide‐loaded evanescent‐mode bandpass filter

In this article, a filter size reduction of 46% is achieved by reducing a substrate‐integrated waveguide (SIW)‐loaded evanescent‐mode bandpass filter to a half‐mode SIW (HMSIW) structure. SIW and HMSIW filters with 1.7 GHz center frequency and 0.2 GHz bandwidth were designed and implemented. Simulation and measurements of the proposed filters utilizing combline resonators have served to prove the underlying principles. SIW and HMSIW filter cavity areas are 11.4 and 6.2 cm², respectively. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Use of 3D field simulators in the synthesis of waveguide capacitive iris coupled lowpass filters

This paper presents the generalized lowpass filter design method of Levy based on three‐dimensional electromagnetic analysis and discontinuity modeling using commercially available full‐wave electromagnetic simulators. It shows how to use Levy's method for very accurate theoretical design of a waveguide capacitive iris lowpass filter, using modern 3D EM field‐solvers based on the finite element method (FEM), the mode matching method (MM), and the transmission line matrix (TLM) analysis method. This is the first time that design curves and equations, based on full electromagnetic modeling, have been presented for constant thickness capacitive iris filters. We will demonstrate our approach by designing a number of waveguide capacitive iris filters. This paper also demonstrates the generality of the method. This method can be applied to many other types of waveguide lowpass and bandpass filters. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 190–198, 2000.     

2‐D/3‐D switchable displays

Abstract— In this paper, the design of a lenticular‐based 2‐D/3‐D display for mobile applications is described. This display combines look‐around capability with good 3‐D resolution. In order to allow high‐resolution datagraphic applications, a concept based on actively switched lenses has been developed. A very noticeable problem for such displays is the occurrence of dark bands. Despite slanting the lenticular and defocusing the lens, banding becomes unacceptable when the display is viewed from an angle. As a solution, fractional viewing systems to reduce the banding intensity by almost two orders of magnitude is introduced. The resulting 3‐D display can be viewed from any horizontal direction without banding.     

Full‐wave analysis of H‐plane waveguide junction loaded with metallic posts

A hybrid method that combines moment method and mode matching technique is presented to study H‐Plane waveguide discontinuity loaded with metallic posts at the junction of two waveguides. By expanding Eigen modes in waveguides, applying continuity of tangential fields at the discontinuity and finally nulling the tangential electric field on the post surface, a system of algebraic equations is solved to obtain current distribution on the posts and consequently scattering parameters of the structure. Then, as an application, an in‐line dual‐mode rectangular waveguide bandpass filter is analyzed using the proposed method along with generalized scattering matrix method. The numerical results are in good agreement with existing full wave finite element method in high frequency structure simulator (HFSS) results and measurements. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.     

Miniaturized planar ferrite junction circulator in the form of substrate‐integrated waveguide

The theoretical analysis and engineering implementation of the planar substrate‐integrated waveguide (SIW) ferrite junction circulator have been proposed in this article. The ferrite junction circulator is implemented in the form of SIW, taking the features of low profile, small volume and easy integration with other planar circuits. The design strategies of the device have been introduced, including the design consideration of the microstrip transition. One C‐band prototype of SIW ferrite junction circulator has been fabricated and measured. The experimental results indicate the bandwidth is about 33% at −15 dB isolation and the maximum isolation is near 40 dB. However, the insertion loss is a little big, owing to the imperfect dielectric material and fabrication inaccuracy. The SIW ferrite junction circulator and the microstrip transition are integrated into a same substrate, resulting in a very compact planar ferrite junction circulator and indicating potential applications in integrated communication and radar systems. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

High‐visibility 2‐D/3‐D LCD with HDDP arrangement and its optical characterization methods

Abstract— A 3.1‐in.‐diagonal 2‐D/3‐D LCD with a novel pixel arrangement, called horizontally double‐density pixels (HDDP), for high‐quality 3‐D images has been developed. 3‐D visibility has been improved by broadening the qualified stereoscopic viewing space (QSVS) where high‐quality 3‐D images can be seen. In order to evaluate the QSVS, optical characterization methods, based on the ergonomics for stereoscopy, such as 3‐D crosstalk, interocular luminance difference and 3‐D moiré have been proposed. The implementation results show that these methods can correctly evaluate high‐visibility autostereoscopic displays.     

2‐D/3‐D displays based on switchable lenticulars

Abstract— An attractive concept for 3‐D displays is the one based on LCDs equipped with lenticular lenses. This enables autostereoscopic multiview 3‐D displays without a loss in brightness. A general issue in multiview 3‐D displays is their relatively low spatial resolution because the pixels are divided among the different views. To overcome this problem, we have developed switchable displays, using liquid‐crystal (LC) filled switchable lenticulars. In this way, it is possible to have a high‐brightness 3‐D display capable of fully exploiting the native 2‐D resolution of the underlying LCD. The feasibility of LC‐filled switchable lenticulars was shown in several applications. For applications in which it is advantageous to be able to display 3‐D and 2‐D content simultaneously, a 42‐in. locally switchable prototype having a matrix electrode structure was developed. These displays were realized using cylindrically shaped lenticular lenses in contact with LC. An alternative for these are lenticulars based on gradient‐index (GRIN) LC lenses. Preliminary results for such switchable GRIN lenses are presented as well.     

Switching directional BLUs for full‐resolution auto‐stereoscopic 3D/2D and 2D/3D LCDs

Directional backlight unit (BLU) design concept was applied to realize full‐resolution field alternate auto‐stereoscopic liquid crystal displays (LCDs) with built‐in 3D/2D and 2D/3D. The application‐oriented BLU design requires priority in realizing 2D mode or 3D mode. The switching characteristic of BLU with two confronting illuminating sets was applied to build 2D mode into 3D display and 3D mode into 2D display. An LCD with 2D mode as primary function requires higher double‐sided luminance uniformity than 3D mode. On the other hand, an LCD with 3D mode requires higher single‐sided luminance uniformity than 2D mode. For increasing the double‐sided luminance uniformity for 2D mode as a primary function of the display, the former BLU design was realized by using uniform prismatic structure, that is, using uniform bilateral prismatic structure with a cross section of isosceles triangle on the back surface of the light‐guide plate. For increasing single‐sided luminance uniformity for 3D mode as a primary function of the display, the latter was realized by using graded angle design, that is, unilateral prisms with a cross section of a scalene triangle on the back surface of the light‐guide plate. The LCDs of small‐sized‐handheld game devices and still cameras were fabricated using the 3D/2D and 2D/3D displays.     

Dual‐lenticular‐lens‐based 2‐D/3‐D convertible autostereoscopic display

Abstract— A 2‐D/3‐D convertible display using two lenticular lenses has been developed. It shows 2‐D pictures in full resolution and 3‐D autostereoscopic pictures in half resolution by moving one lens relative to the other. The lens assembly consists of thin metal frames, two lenticular lenses, and two shape‐memory‐alloy (SMA) wires used as actuators. While this assembly is applicable to flat‐panel displays of any kind, its simple structure and low power consumption make it best suited to mobile terminals, such as PDAs and mobile phones. Here, we describe its structure and present evaluation results.     

Invited Paper: Depth reproducibility of multiview depth‐fused 3‐D display

Abstract— A multi‐view depth‐fused 3‐D (DFD) display that provides smooth motion parallax for wide viewing angles is proposed. A conventional DFD display consists of a stack of two transparent emitting screens. It can produce motion parallax for small changes in observation angle, but its viewing zone is rather narrow due to the split images it provides in inclined views. On the other hand, even though multi‐view 3‐D displays have a wide viewing angle, motion parallax in them is discrete, depending on the number of views they show. By applying a stacked structure to multi‐view 3‐D displays, a wide‐viewing‐angle 3‐D display with smooth motion parallax was fabricated. Experimental results confirmed the viewing‐zone connection of DFD displays while the calculated results show the feasibility of stacked multi‐view displays.     

Effect of 3D depth on the resolution and the observed image for auto‐stereoscopic multi‐view 3D display

In auto‐stereoscopic multi‐views, blurring occurs due to the incomplete separation of views for non‐zero depths. How this blur affects a 3D image was investigated using the commercial multi‐view 3D. The 3D input signal consisted of the square pattern and the gratings of various width and gray level values of G1 and G2. The various combinations of G1 and G2 were used to investigate the dependence of blur on gray G1 and G2 values. The 3D depth caused blurring, which caused a decrease in contrast modulation. Hence, the 3D resolution determined from contrast modulation was affected by the depth and became worse with increasing depth. Therefore, 3D resolution may be used to define the depth range within which the image degradation due to blurring is acceptable. Blur edge width values at the boundaries of gray G1 and G2 were measured and found to be similar irrespective of G1 and G2 values at the same depth. This was because blur was caused by the incomplete separation of views that are independent of G1 and G2. Hence, the blurriness of the observed 3D image is determined only by the depth. The 3D resolution and blur edge width might be useful to characterize the performance of auto‐stereoscopic multi‐view 3D.     

Development of a 42‐in. 2‐D/3‐D switchable display using multi‐view technology for public‐information‐display applications

Abstract— A 42‐in. 2‐D/3‐D switchable display operating in a parallax‐barrier‐type system consisting of liquid‐crystal displays (LCDs) has been developed. The system displays 2‐D images in full resolution, without any degradation to the original 2‐D images, and 3‐D autostereoscopic images with resolutions higher than SVGA with wide viewing zones electrically controlled by the parallax‐barrier system. The system is intended for use in public‐information displays (PIDs), a booming field, and as displays for gaming, medical, and simulation applications.     

2‐D D3LS algorithm with mutual coupling

New adaptive algorithm of direct data domain is presented which can recover the signal in the presence of mutual coupling. The proposed algorithm can estimate the coupling coefficients without utilizing any auxiliary sensors. Numerical simulation shows that the proposed algorithm can accurately recover the signal in the presence of mutual coupling. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Radiation characteristics of strip‐loaded dielectric‐coated conducting cylinder

The radiation characteristics of strip‐loaded dielectric‐coated conducting cylinder are investigated theoretically for the infinite and finite periodic structures. For the infinite case, the strip electric current expansion satisfying edge condition and the field expression with a summation of space harmonics are applied to solve a homogeneous matrix equation. The integral equation is derived for the finite structure by using the inverse Fourier transform and the strip current expansion. The influences of the strip width, cylinder radius, and finite strip number on the radiation characteristics (leakage constant, phase constant, radiation pattern, and beam scanning) are investigated. The results of the finite periodic strips are compared with those of the infinite extent structure and good agreement is found. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

A 470 × 235‐ppi poly‐Si TFT‐LCD for high‐resolution 2‐D and 3‐D autostereoscopic displays

Abstract— We have developed a 470 × 235‐ppi poly‐Si TFT‐LCD with a novel pixel arrangement, called HDDP (horizontally double‐density pixels), for high‐resolution 2‐D and 3‐D autostereoscopic displays. 3‐D image quality is especially high in a lenticular‐lens‐equipped 3‐D mode because both the horizontal and vertical resolutions are high, and because these resolutions are equal. 3‐D and 2‐D images can be displayed simultaneously in the same picture. In addition, 3‐D images can be displayed anywhere and 2‐D characters can be made to appear at different depths with perfect legibility. No switching of 2‐D/3‐D modes is necessary, and the design's thin and uncomplicated structure makes it especially suitable for mobile terminals.     

MUTED: Multi‐user 3‐D display

Abstract— Research described in this paper encompasses the design and building of glasses‐free (autostereoscopic) displays that utilize a direct‐view liquid‐crystal display whose backlight is provided by a projector and novel steering optics. This is controlled by the output of a multi‐user head‐position tracker. As the displays employ spatial multiplexing on a liquid‐crystal‐display screen, they are inherently 2‐D/3‐D switchable with 2‐D being achieved by simply displaying the same image in the left and right channels. Two prototypes are described in this paper; one incorporating a holographic projector and the other a conventional LCOS projector. The LCOS projector version addresses the limitations of brightness, cross‐talk, banding in the images, and laser stability that occur in the holographic projector version. The future development is considered and a comparison between the prototypes and with other 3‐D displays is given.     

Video 2‐D—to—3‐D conversion based on hybrid depth cueing

Abstract— With the maturation of three‐dimensional (3‐D) technologies, display systems can provide higher visual quality to enrich the viewer experience. However, the depth information required for 3‐D displays is not available in conventional 2‐D recorded contents. Therefore, the conversion of existing 2‐D video to 3‐D video becomes an important issue for emerging 3‐D applications. This paper presents a system which automatically converts 2‐D videos to 3‐D format. The proposed system combines three major depth cues: the depth from motion, the scene depth from geometrical perspective, and the fine‐granularity depth from the relative position. The proposed system uses a block‐based method incorporating a joint bilateral filter to efficiently generate visually comfortable depth maps and to diminish the blocky artifacts. By means of the generated depth map, 2‐D videos can be readily converted into 3‐D format. Moreover, for conventional 2‐D displays, a 2‐D image/video depth perception enhancement application is also presented. With the depth‐aware adjustment of color saturation, contrast, and edge, the stereo effect of the 2‐D content can be enhanced. A user study on subjective quality shows that the proposed method has promising results on depth quality and visual comfort.