Change search
ReferencesLink to record
Permanent link

Direct link
Co-Design of Antenna and LNA for 1.7 - 2.7 GHz
Linköping University, Department of Science and Technology, Physics and Electronics. (Communication Electronics)
Linköping University, Department of Science and Technology, Physics and Electronics.
2012 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

In a radio frequency (RF) system, the front-end of a radio receiver consists of an active antenna arrangement with a conducting mode antenna along with an active circuit. This arrangement helps avoid losses and SNR degradation due to the use of a coaxial cable. The active circuit is essentially an impedance matching network and a low noise amplification (LNA) stage. The input impedance of the antenna is always different from the source impedance required to be presented at the LNA input for maximum power gain and this gives rise to undesired reflections at the antenna-LNA junction. This necessitates a matching network that provides the impedance matching between the antenna and the LNA at a central frequency (CF). From the Friis formula it is seen that the total noise figure (NF) of the system is dependent on the noise figure and gain of the first stage. So, by having an LNA that provides a high gain (typically >15 dB) which inserts minimum possible noise (desirably < 1 dB), the overall noise figure of the system can be maintained low. The LNA amplifies the signal to a suitable power level that will enable the subsequent demodulation and decoding stages to efficiently recover the original signal. The antenna and the LNA can be matched with each other in two possible ways. The first approach is the traditional method followed in RF engineering where in both the antenna and LNA are matched to 50 W terminations and connected to each other. In this classical method, the antenna and LNA are matched to 50 W at the CF and does not take into account the matching at other frequencies in the operation range. The second approach employs a co-design method to match the antenna and LNA without a matching network or with minimum possible components for matching. This is accomplished by varying one or more parameters of either the antenna or LNA to control the impedances and ultimately achieve a matching over a substantial range of frequencies instead at the CF alone. The co-design method is shown to provide higher gain and a lower NF with reduced number of components, cost and size as compared to the classical method.

The thesis work presented here is a study, design and manufacturing of an antenna-LNA module for a wide frequency range of 1.7 GHz – 2.7 GHz to explore the gain and NF improvements in the co-design approach. Planar micro strip patch antennas and GaAs E-pHEMT transistor based LNA’s are designed and the matching and co-design are simulated to test the gain and NF improvements. Furthermore, fully functional prototypes are developed with Roger R04360 substrate and the results from simulations and actual measurements are compared and discussed. 

Place, publisher, year, edition, pages
2012. , 67 p.
Keyword [en]
ADS, LNA, Antenna, NF, co-design, codesign, E-pHEMT
National Category
Communication Systems
URN: urn:nbn:se:liu:diva-85953ISRN: LiU-ITN-TEK-A--12/046--SEOAI: diva2:574230
Subject / course
Master's Programme in Wireless Networks and Electronics, 120 ECTS
2012-08-13, TP31, Campus Norrköping, Norrköping, Sweden, Norrköping, 23:51 (English)
Available from: 2012-12-05 Created: 2012-12-04 Last updated: 2015-03-18Bibliographically approved

Open Access in DiVA

Co-Design of Antenna and LNA for 1.7 - 2.7 GHz(4398 kB)623 downloads
File information
File name FULLTEXT01.pdfFile size 4398 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Jacob, KaneGudey, Bala Bhaskar
By organisation
Physics and Electronics
Communication Systems

Search outside of DiVA

GoogleGoogle Scholar
Total: 623 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 427 hits
ReferencesLink to record
Permanent link

Direct link