Nonlinearity Improvement of Antennas, Filters and Amplifiers for a RF Front-End Module
| Autor: | Han-Jan Chen, 陳漢珍 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 With rapid growth of wireless local area network (WLAN), the trends of high video/sound/data transmission and internet everywhere are increased day by day. Thus, the requirements of compact size, light weight and high performance are necessary; in addition, the trends of multi-function and multi-band operations in a module are also more important in communication products design. It means that people can communicate everywhere and every time, and make our life rich, leading to portable and wearable personal communication services. With progresses of communication technologies the specifications of devices and systems are more and more strict so that easy to fabrication and multi-function components will become main streams. However, the stricter specifications of systems will lead the engineers difficult to design; besides, nonlinear effects will demonstrate the overall characteristics of communication systems. Therefore, nonlinear effects of components would be studied in this dissertation. For our purposes, these nonlinear effects would be cancelled or suppressed without increasing component size and changing passband characteristics. Moreover, effects of quality factors on components are also studied and demonstrated by design an amplifier. At first, we introduce the communication protocols to study the requirements of components and systems, and to give an example of IEEE 802 series standards. In order to meet our purposes we also compare with trends of industry markets and scholarly researches to be our knowledge. Suppressions of nonlinear effects have been proposed by using the concept of photonic bandgap (PBG), including electromagnetic bandgap (EBG) and defected ground structure (DGS). Their applications are widely in antennas, filters, power amplifiers, voltage-controlled oscillators, mixers etc. However, design of PBG structure is more difficult due to its complex theory and many structure parameters. Therefore, based on transmission-line model and lowpass filter prototype the DGS structures are used to study and qualitative analyze. In our study, different periods of DGS structures would cause different performances, such as wider stopband bandwidth and higher stopband attenuations. Moreover, a cross-shape DGS (CSDGS) structure is proposed and its physical model is also established. Good-in-band passband flatness, high attenuation rate and ultra-wide stopband bandwidth can be given in proposed CSDGS structure. To consider the package problem the proposed CSDGS structure can be integrated easily with multi-layer design and SIP (system in packaging) techniques. Filters are important key components due to their high selectivity. However, large size and nonlinear effect of spurious response are their serious problems. One advantage of dual-mode filters is small size, however, orthogonal input/output (I/O) and spurious responses are limited its applications. Based on transmission-line model and network theory, a pair of transmission zeros are generated by cross-coupling effect, meaning that if we can provide a solution to generation of cross-coupling effect, then the orthogonal I/O should be not necessary. Moreover, high-order modes are also affected by I/O configurations. It means that the spurious responses can be controlled or suppressed by different I/O configurations. Therefore, we propose a simple approach of irregularly distributing high-order mode to suppress spurious responses. Finally, two types of non-orthogonal I/O and other two types of spurious suppression dual-mode filters are designed to demonstrate. How to suppress image and harmonic signals has been an important issue in design of the superheterodyne architectures. Due to system linearity and IQ modulation, image and harmonic signals should be suppressed. Therefore, we propose the image-rejection low noise amplifier (LNA) without increasing element order by using a classical filter synthesis method to matching networks. Moreover, to consider packaging grounding problems the package-induced cross-coupling effect is studied to suppress harmonic signals. Finally, both image and harmonic signals can be suppressed in a LNA at the same time. Quality factor is an essential design consideration on passive devices, such as antennas and filters. In this dissertation, quality factors of substrates are studied to analyze effects on active components, including noise figure and realization of ideal lumped-element. In order to provide a complete solution, the improved DLTL (different-length transmission-line) method is proposed to accurately measure dielectric characteristics of substrates for a wide band and both of electric properties and physical meanings have studied, as well. Moreover, a compound component of amplifier with high selectivity and wide stopband bandwidth is designed to demonstrate the effect of quality factor. Finally, the proposed concept and design method can be widely applied to each component and fabrication technology, such as LTCC technique. Then, design and fabrication of high-Q capacitance and inductance on the substrates of semi-conductors will be future works. Moreover, signal integrity is also an important study. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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