Design amd implementation of a VHF/UHF front-end using tunable dual band filters

Download

index.pdf

Date

2012

Author

Alaca, Fatih

Metadata

Show full item record

Item Usage Stats

172
views

88
downloads

For the new generation wireless communication systems, there is an increasing demand for devices that covers more than one frequency band. This results in a need for wide-band tunable front-ends. The main objective of this study is to use dual band filters in the design of a multi-band front-end. A wide-band low noise amplifier is also required. To accomplish this project, a fixed frequency bandstop filter, a tunable dual-band filter and a wide-band LNA are designed and implemented successfully. The predefined specifications of this front-end include gain, gain flatness, spurious signal rejection, frequency tuning range, noise figure and linearity. Total power dissipation and number of elements are also taken into consideration. Test results of the manufactured front-end are compared with the results of existing single band front-ends. In order to design a good tunable wide-band filter, just tuning its center frequency will not be enough. The noise figure of this dual-band filter will be proportional to its insertion loss if it will be used as a pre-selection filter in front of a LNA. Hence its insertion loss will affect the overall noise figure of the system. If it will be used after the LNA, its linearity will be more important. When a bandpass filter is tuned over wide range of frequencies, its bandwidth varies significantly which leads to a degradation in rejection of the spurious signals. Therefore, there must be a simultaneous control of center frequency, bandwidth and insertion loss while providing enough linearity. In order to accomplish this mission, a filter that has two passbands is designed and implemented. The first passband is tunable between 136MHz and 174MHz while the second one is tunable between 380MHz and 470MHz. Also, the low noise amplifier works properly between 136MHz and 470MHz. As a result, a front-end that covers two bands is obtained.

Subject Keywords

Wireless communication systems., Wireless LANs., Frequency changers., Frequency multipliers.

URI

http://etd.lib.metu.edu.tr/upload/12614421/index.pdf
https://hdl.handle.net/11511/21609

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Linerization of RF-power amplifiers by using memory polynomial digital predistortion technique Erdoğdu, Gözde; Demir, Şimşek; Yüzer, Hayrettin; Department of Electrical and Electronics Engineering (2012) In modern wireless communication systems, new modulation types are introduced in order to support more users by considering spectral efficiency. These new signals are ensitive to nonlinearity when they have high peak to average ratio. The main part in the system that causes nonlinearity is the power amplifier. For power amplifiers, between linearity and efficiency, there is a trade-off. However, by using predistortion techniques, both linearity and efficiency can be obtained. In this thesis, various predist...
Design of Tunable Amplifier Using Digital Capacitors Atilla, Dogu Cagdas; Aydin, Cagatay; Nesimoglu, Tayfun; KÖPRÜ, RAMAZAN; Aksen, Ahmet; Yarman, B. S. (2014-12-14) In recent days, radio manufacturers are increasingly interested in broadband amplifiers for cellular communication. Demands of customers enforce manufacturers to develop systems compatible for all standards and it is mandatory to accommodate more than one amplifier or tunable amplifier in front end of communication systems. In this paper, design of tunable amplifier is investigated by using Real Frequency Technique and agility of tunable components is provided by digital tunable capacitors.
Design of dual-frequency probe-fed microstrip antennas with genetic optimization algorithm Ozgun, O; Mutlu, S; Aksun, MI; Alatan, Lale (2003-08-01) Dual-frequency operation of antennas has become a necessity for many applications in recent wireless communication systems, such as GPS, GSM services operating at two different frequency bands, and services of PCS and IMT-2000 applications. Although there are various techniques to achieve dual-band operation from various types of microstrip antennas, there is no efficient design tool that has been incorporated with a suitable optimization algorithm. In this paper, the cavity-model based simulation tool alon...
A novel user activity prediction model for context aware computing systems Peker, Serhat; Koçyiğit, Altan; Department of Information Systems (2011) In the last decade, with the extensive use of mobile electronic and wireless communication devices, there is a growing need for context aware applications and many pervasive computing applications have become integral parts of our daily lives. Context aware recommender systems are one of the popular ones in this area. Such systems surround the users and integrate with the environment; hence, they are aware of the users' context and use that information to deliver personalized recommendations about everyday ...
A Low-complexity, near-optimal scheduling policy for solving a restless multi-armed bandit problem occurring in a single-hop wireless network / Gül, Ömer Melih; Uysal Bıyıkoğlu, Elif; Department of Electrical and Electronics Engineering (2014) Power resources and battery lifetime are important issues for wireless networks such as wireless sensor networks (WSNs). To extend the battery lifetime, the recent advances in energy harvesting (EH) techniques propose an effective solution. EH nodes can harvest energy from environmental sources (e.g. solar, wind, vibrational, thermal) to power their sensing, computing and communication functions. In this thesis, we develop a solution to a scheduling problem under three scheduling scenarios. Firstly, we cons...

Citation Formats

F. Alaca, “Design amd implementation of a VHF/UHF front-end using tunable dual band filters,” M.S. - Master of Science, Middle East Technical University, 2012.