Entity

Time filter

Source Type

Salisbury, MD, United States

Fathelbab W.M.,K and L Microwave
IET Microwaves, Antennas and Propagation | Year: 2015

This study presents the synthesis and design of novel bandpass prototype networks with reconfigurable centre frequencies in two distinct states whose absolute bandwidth is maintained constant. The passbands of the prototypes can also be tuned around the centre frequencies of the two distinct states with minimal absolute bandwidth variation. This is achieved by virtue of a new distributed resonator structure which is thoroughly studied and analysed in this work. The presented circuit concepts are validated through the simulation of a stub-loaded evanescent mode waveguide filter modelled on high frequency structure simulator (HFSS) realising an absolute bandwidth of 242 MHz in two distinct states that are centred at frequencies of 1150 and 1495 MHz. The filter is manually reconfigured between the two distinct states upon terminating stubs within its resonator structures as either open-circuits or short-circuits. The filter is also discretely tuned in each of the two states upon manually altering the values of the loading capacitors of its resonators. The absolute bandwidth of the filter exhibited a maximum variation of only ±28 MHz over the frequency tuning range spanning 977.5 to 1667.5 MHz. © The Institution of Engineering and Technology. Source


Fathelbab W.M.,K and L Microwave
IET Microwaves, Antennas and Propagation | Year: 2015

This study presents the synthesis and design of novel band-reject filters whose frequency characteristics can be reconfigured between two distinct states, each of which is centred at a different resonant frequency. The absolute bandwidth of the reconfigurable filters in the two distinct states is maintained constant by virtue of introducing two new resonator types which are thoroughly studied and analysed in this work. The synthesis of two prototype networks realising a common electrical specification is illustrated and each network is subsequently transformed into two types of band-reject filters comprising novel coupled-line sections. The presented circuit concepts are then validated through the simulation of a suspended-substrate stripline filter modelled utilising high frequency structure simulator (HFSS) which realises an absolute bandwidth of 200 MHz in the two distinct states centred at 1180 and 1485 MHz. The HFSS filter model is manually reconfigured between the two distinct states upon terminating stubs within each of its resonator structures as either open circuit or short circuit. The performance of the HFSS filter model shows close correspondence to the performance of the synthesised prototype network, thus demonstrating the validity of the proposed circuit principles. © The Institution of Engineering and Technology 2015. Source


Qudrat-Ullah H.,York University | Seong B.S.,Konkuk University | Mills B.L.,K and L Microwave
International Journal of Technology Management | Year: 2012

This paper draws on extensive theoretical research and literature reviews, from two cases, and presents one case to illustrate practical application. It seeks to define and understand how lean product development integrates with current lean manufacturing strategies, and how the principles of the lean product development process can successfully be applied to improve the operations of a high variable-low volume product mix business. This work aims at delivering a unique conceptual model that demonstrates how businesses can improve their profitability through the utilisation of lean product development concepts. Through our conceptual model, business firms achieve the systemic integration of lean product development concepts with their downstream operations. The case presented of a high variable-low volume business organisation offers useful insights into how to implement this in practice. © 2012 Inderscience Enterprises Ltd. Source


Howett D.,Microwave Products Group | Busse M.P.,Microwave Products Group | Rawlinson D.,B.sc. | Burkett J.,K and L Microwave | And 3 more authors.
Microwave Journal | Year: 2014

The history of advances in the development of RF and microwave filters is well documented, and broad innovations objectives have remained essentially the same over decades. Additionally, advanced ceramic materials have made dielectrically-loaded waveguide super high Q filters possible. System computing technology has expanded possibilities for filtering cancellation techniques, driving some agile filter technology. Cavity-like performance and Q are being sought in surface mount formats. Amplifier semi-conductor materials have lowered noise figures, allowing higher filter insertion loss to be traded for smaller filter sixe while maintaining overall system cascaded noise. The design process starts by forming a transmission line model, developing the filter order and preliminary physical layout required. Source

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