22 research outputs found
Reconfigurable RF Circuits and RF‐MEMS
No full textThe twelfth chapter, Reconfigurable RF Circuits and RF-MEMS, was contributed by Robert Malmqvist from Swedish Defence Research Agency (FOI) and Uppsala University, Sweden, Aziz Ouacha from FOI, Sweden, Mehmet Kaynak from IHP GmbH, Frankfurt (Oder), Germany, Naveed Ahsan Linköping University, Sweden, and Joachim Oberhammer from KTH Royal Institute of Technology, Stockholm, Sweden. While most of today's RF circuits are designed for a specific (fixed) function and frequency range, a much higher degree of flexibility would be possible using highly reconfigurable circuit implementations and front-ends architectures. This chapter presents examples of reconfigurable RF circuits that have been realised using either fully transistor based solutions or by employing RF MicroElectroMechanical Systems (RF-MEMS). First a novel approach for implementing reconfigurable circuitry based on the concept of Programmable Microwave Function Arrays (PROMFA) is presented. Various reconfigurable circuit designs based on the emergence of high performance RF-MEMS switches being developed in GaAs, GaN and SiGe RFIC/MMIC process technologies are then reviewed. In the final section, an overview of state-of-the-art RF-MEMS based phase shifter designs intended for electronic beam-steering antennas and phased array systems is presented.</p
A microwave-based multifunction system. Concept : A necessity for network centric warfare
No full textDual Band Tunable LNA for Flexible RF Front End
No full textThis paper presents a dual band LNA that can be switched between two bands (2.4 GHz & 5.2 GHz) for IEEE 802.1 la/b/g WLAN applications. The LNA is also tunable within each band and the tuning is incorporated by on-chip varactors. The test chip consists of two fully integrated narrow-band tunable LNAs along with SPDT switch. For power saving one LNA can be switched off. The technology process is 0.2 mum GaAs offered by OMMIC. The LNA can achieve a relatively good performance over the two bands as demonstrated by simulation. With a 3V supply, the LNA has a gain of 26.2 dB at 2.4 GHz and 21.8 dB at 5.2 GHz and the corresponding NF varies between 2.07 dB and 1.84 dB, respectively. The LNA has an IIP3 of -7 dBm at 2.4 GHz and -1.6 dBm at 5.2 GHz.</p
Receiving by giving:The examining of cross-border diasporic and bi-cultural philanthropy
No full textReceiving by Giving is an interdisciplinary, intersectional and in-depth examination of cross-border diasporic and bi-cultural philanthropy embodied in a PhD manuscript. By taking the socio-geographical case study of the Netherlands and Morocco, the author explains the multi-layered cross-border philanthropy performed by (150 Dutch-Moroccan) diaspora and bi-cultural philanthropists from the country of residence to the homeland
Receiving by giving:The examining of cross-border diasporic and bi-cultural philanthropy
No full textReceiving by Giving is an interdisciplinary, intersectional and in-depth examination of cross-border diasporic and bi-cultural philanthropy embodied in a PhD manuscript. By taking the socio-geographical case study of the Netherlands and Morocco, the author explains the multi-layered cross-border philanthropy performed by (150 Dutch-Moroccan) diaspora and bi-cultural philanthropists from the country of residence to the homeland
Applications of Programmable Microwave Function Array (PROMFA)
No full textThis paper describes the use of programmable microwave function array (PROMFA) for different microwave application. The PROMFA concept is based on an array of generic cells, in which a number of different functions can be realized. Each PROMFA cell is a four-port circuit, that can either be programmed independently or collectively according to a specific need. Specifically, the phase shift capability in a single PROMFA cell, useful for a new type of phase shifter design is discussed. The paper also presents the functionality of this new architecture as a beamforming network. As an example case an active corporate feed network and a tunable recursive filter is demonstrated. Simulated and measured results are presented.</p
A Self-Tuning Technique for Optimization of Dual Band LNA
No full textThis paper presents a self-tuning technique for optimization of a dual band LNAthat can be used in a flexible RF front-end suitable for IEEE 802.11a/b/g WLANapplications. With this tuning technique the LNA can perform self-calibrationfor the optimal performance. A possible shift in resonance frequency due toprocess and temperature variations can be compensated by this method. Theproposed self-tuning technique is implemented by using a simple RF detector atthe LNA output. Based on the DC value provided by this detector the LNA istuned for a maximum gain through the tuning loop, which incorporates ADC,digital base-band and DAC. We show that the tuning error can be within halfLSB of ADC provided the DAC and ADC resolutions are constraint by aspecified condition. For 4-bit case this value corresponds to a gain error of0.4 dB. The LNA has been implemented in 0.2μm GaAs process offered byOMMICTM. In measurements the LNA achieves a gain of 15.1 dB and 21.6 dBin the upper and lower band, respectively, with corresponding NF of 3.8 dB and2.8 dB. In the lower band the measured IIP3 is -3 dBm and 1dB_CP is -8 dBm.</p
