نتایج جستجو برای: Dual Band

تعداد نتایج: 285181  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده مهندسی برق و الکترونیک 1392

حلقه های قفل شده فاز تمام دیجیتال یکی از مباحث مهم در دنیای امروز الکترونیک هستند. حلقه قفل فازهای (pll ) که به وسیله روشهای آنالوگ طراحی می شدند نسبت به تغییرات دما و ولتاژ و پروسس حساس بودند. این امر موجب سختی طراحی و نیازمندی به طراحی مجدد در تکنولوژی های جدید می شود. این در حالی است که با استفاده از حلقه های قفل فاز تمام دیجیتال این مشکلات برطرف میشوند. حلقه های قفل فاز تمام دیجیتال (adpll...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان - دانشکده برق 1392

متامتریال یا فراماده یک ساختارمصنوعی وهمگن است که خواص غیرعادی الکترومغناطیس ازخود نشان میدهد.مواد دست چپی که دارای εو μمنفی میباشند،دارای خواص فراماده میباشند.اما مواد دست چپی خالص را نمیتوان ایجادکرد؛ به دلیل وجودعناصرپارازیتیک درفرکانس های بالا،همواره ترکیبی ازمواد دست راستی و دست چپی وجود داردکه به آنها crlh میگویند. به دلیل خواص منحصربه فردی که خطوط دست چپی از خود نشان میدهند،میتوان درطراح...

A dual-band artificial magnetic material and then a dual-band double-negative metamaterial structure based on symmetric spiral resonators are presented. An approximate analytical model is used for the initial design of the proposed structures. The electromagnetic parameters of the proposed metamaterial structure retrieved using an advanced parameter retrieval method based on the causality princ...

Journal: :international journal of communications and information technology 2011
n. ojaroudi m. ojaroudi s. amiri

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...

مرادی, خاطره , نیک‌مهر, سعید ,

In this paper, a simple dual-band dual-polarized aperture stacked patch antenna with double sided notch is presented. This antenna is suitable for operation in telecommunication base stations. One of the bands covers the GSM band, while the other covers both DCS and UMTS bands. The proposed antenna shows good port decoupling of less than -30dB for dual linear polarization over its operating ban...

Abstract - This paper presents a new design of microwave microelectromechanical systems (MEMS) phase shifter for dual band wireless local area network (WLAN) applications. A bit is designed which product a constant phase shift of 11.25° by switching between two line that consist of 12 and 6 unitcells in each frequency band. A unitcell is constructed by gold membrane suspended over the coplanar ...

A new multi-layer substrate integrated waveguide (SIW) structure is developed to design dual-band evanescent-mode band-pass filters (BPFs). Two independent series LC circuits are implemented by incorporating metallic irises in the different layers of the structure. The combination of the metallic irises with capacitive-plates is embedded inside the SIW to independently excite two evane...

Infrared imagers are important for reorganization and monitoring. This paper discusses the design of an infrared imager. Optical design in medium wavelength infrared (MWIR) and long wavelength infrared (LWIR) bands is different and needs distinct detectors and materials. Reflective systems are not suitable due to their small field of view (FOV) and vignetting. Refractive dual band optical syste...

In this paper, two compact quad-channel and six-channel diplexer are designed and fabricated using defected microstrip structure (DMS). This structure is designed for the desired frequency based on the literature reviews. The proposed configuration is composed of a conventional T-junction divider with two pairs of open bended stubs and dual/tri-band filters. In designing dual band filters, a lo...

Journal: :journal of communication engineering 0
morteza nadi iran university of science and technology mohammad hosein fakheri department of electrical engineering, iran university of science and technology ali abdolali department of electrical engineering, iran university of science and technology

body centric wireless communication (bcwc) has been the topic of much research in recent years. in this manuscript, a novel low-cost microstrip patch antenna is designed for on-/off-body communications with a dual-band operation. the proposed structure exhibits a monopole-like radiation pattern at 2.45ghz and a broadside radiation at 4.8ghz, simultaneously. lateral dimensions of 42 mm × 46 mm a...

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