Broadband microwave diode mixer design and implementation

Koç, Emrah
Mixers play a critical role in design and development of wireless communication systems. Demanding requirements of the mixers are improvements in conversion efficiency, bandwidth, cost, and linearity. Schottky barrier diodes attract mixer designers due to their favorable characteristics leading to wide bandwidth, low-cost, and high efficient designs. This thesis demonstrates the design and implementation of two passive mixing circuits using Schottky barrier diodes at microwave frequencies. The first circuit is a broadband mixer which operates between 2 GHz and 18 GHz for RF/LO frequency with an average conversion loss of 7 dB. It provides LO-RF and RF-IF isolation of 30 dB over the most frequencies across the band. Furthermore, IIP3 of 13 dBm is achieved for LO drive level of 13 dBm. The second design proposes improved IF bandwidth up to 4 GHz. Conversion loss of 6 dB is typically measured for the RF frequency of 5 GHz-15 GHz. It shows excellent LO-RF isolation of better than 35 dB across the frequency band with similar IIP3 performance of first design.  


X-band high power GaN power amplifier design and implementation
Işık, Ali İlker; Demir, Şimşek; Department of Electrical and Electronics Engineering (2016)
High frequency power amplifiers play a crucial role in design, development and overall performance of wireless communication systems. Demanding requirements of the power amplifiers require improvements in output power, efficiency and bandwidth. GaN devices attract high frequency power amplifier designers due to the superior material characteristics of GaN. In this thesis, a power amplifier operating at X-band is designed and realized using a GaN discrete bare die transistor. It provides over 15 W output pow...
Design of a reduced complexity rateless spinal decoder
Taş, Murat; Diker Yücel, Melek; Department of Electrical and Electronics Engineering (2014)
Wireless communication systems utilize several forward error correcting techniques to cope with changing channel conditions efficiently. One way is selecting from a list of coding/modulation schemes by considering the actual channel state. When this approach of choosing a fixed rate code is not applicable, one can use rateless codes whose rates are dynamically changing with respect to the changing channel conditions. A rateless encoder continues to send its codeword/packet to the destination unless the rece...
Finite-horizon online energy-efficient transmission scheduling schemes for communication links
Bacınoğlu, Baran Tan; Uysal Bıyıkoğlu, Elif; Department of Electrical and Electronics Engineering (2013)
The proliferation of embedded systems, mobile devices, wireless sensor applications and increasing global demand for energy directed research attention toward self-sustainable and environmentally friendly systems. In the field of communications, this new trend pointed out the need for study of energy constrained communication and networking. Particularly, in the literature, energy efficient transmission schemes have been well studied for various cases. However, fundamental results have been obtained mostly ...
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...
Routing and security in wireless sensor networks, an experimental evaluation of a proposed trust based routing protocol
Chalabianloo, Niaz; İşler, Veysi; Department of Computer Engineering (2013)
Satisfactory results obtained from sensor networks and the ongoing development in electronics and wireless communications have led to an impressive boost in the number of applications based on WSNs. Along with the growth in popularity of WSNs, previously implemented solutions need further improvements and new challenges arise which need to be solved. One of the main concerns regarding WSNs is the existence of security threats against their routing operations. Likelihood of security attacks in a structure su...
Citation Formats
E. Koç, “Broadband microwave diode mixer design and implementation,” M.S. - Master of Science, Middle East Technical University, 2016.