DESIGN OF A MINIATURIZED SOP INTEGRATED GNSS RF FRONT-END MODULE

Navigation devices used to be bulky and expensive and were not widely commercialized for personal use. Nowadays, all useful electronic devices are turning into being handheld so that they can be conveniently used anytime and anywhere. One can claim that almost any mobile phone, used today, has quite strong navigational capabilities that can efficiently work anywhere in the globe. No matter where you are, you can easily know your exact location and make your way smoothly to wherever you would like to go. This couldn’t have been made possible without the existence of efficient and small microwave circuits responsible for the transmission and reception of high quality navigation signals. This thesis is mainly concerned with the design of novel highly miniaturized and efficient filtering components working in the Global Navigational Satellite Systems (GNSS) frequency band to be integrated within an efficient Radio Frequency (RF) front-end module (FEM). A System-on-Package (SoP) integration technique is adopted for the design of all the components in this thesis. Two novel miniaturized filters are designed, where one of them is a wideband filter targeting the complete GNSS band with a fractional bandwidth of almost 50% at a center frequency of 1.385 GHz. This filter utilizes a direct inductive coupling topology to achieve the required wide band performance. It also has very good out-of-band rejection and low IL. Whereas the other dual band filter will only cover the lower and upper GNSS bands with a rejection notch in between the two bands. It has very good inter band rejection. The well-known “divide and conquer” design methodology was applied for the design of this filter to help save valuable design and optimization time. Moreover, the performance of two commercially available ultra-Low Noise Amplifiers (LNAs) is studied. The complete RF FEM showed promising preliminary performance in terms of noise figure, gain and bandwidth, where it out performed other commercial front-ends in these three aspects. All the designed circuits are fabricated and tested. The measured results are found to be in good agreements with the simulations.

Development of a Composite ion-exchange membrane for PDMS-based microfluidic devices

The purpose of this research is to investigate potential methods to produce an ion-exchange membrane that can be integrated directly into a polydimethylsiloxane Lab-on-a-Chip or Micro-Total-Analysis-System. The majority of microfluidic membranes are based on creating microporous structures, because it allows flexibility in the choice of material such that it can match the material of the microfluidic chip. This cohesion between the material of the microfluidic chip and membrane is an important feature to prevent bonding difficulties which can lead to leaking and other practical problems. However, of the materials commonly used to manufacture microfluidic chips, there are none that provide the ion-exchange capability. The DuPont product Nafion{TM} is chosen as the ion-exchange membrane, a copolymer with high conductivity and selectivity to cations and suitable for many applications such as electrolysis of water and the chlor-alkali process. The use of such an ion-exchange membrane in microfluidics could have multiple advantages, but there is no reversible/irreversible bonding that occurs between PDMS and Nafion{TM}. In this project multiple methods of physical entrapment of the ion-exchange material inside a film of PDMS are attempted. Through the use of the inherent properties of PDMS, very inexpensive sugar granulate can be used to make an inexpensive membrane mould which does not interfere with the PDMS crosslinking process. After dissolving away this sacrificial mould material, Nafion{TM} is solidified in the irregular granulate holes. Nafion{TM} in this membrane is confined in the irregular shape of the PDMS openings. The outer structure of the membrane is all PDMS and can be attached easily and securely to any PDMS-based microfluidic device through reversible or irreversible PDMS/PDMS bonding. Through impedance measurement, the effectiveness of these integrated membranes are compared against plain Nafion{TM} films in simple sodium chloride solutions.