A K Gupta
Articles written in Sadhana
Volume 29 Issue 4 August 2004 pp 355-363
The paper presents a study of propagation of Love waves in a poroelastic layer resting over a poro-elastic half-space. Pores contain nothing of mechanical or energetic significance. The study reveals that such a medium transmits two types of love waves. The first front depends upon the modulus of rigidity of the elastic matrix of the medium and is the same as the love wave in an elastic layer over an elastic half-space. The second front depends upon the change in volume fraction of the pores. As the first front is well-known, the second front has been investigated numerically for different values of void parameters. It is observed that the second front is many times faster than the shear wave in the void medium due to change in volume fraction of the pores and is significant
Volume 38 Issue 4 August 2013 pp 667-678
Radio frequency and Microwave (RFM) infrastructure test facility is under development at RRCAT for evaluating and powering, subsystems of particle accelerator. As a part of this facility, design of 20–30 kW UHF solid state power ampliﬁers is in progress. For this work, design procedure has been formulated for the development of solid state ampliﬁer modules, radial combiner, divider and directional coupler; with speciﬁcations suited to RFM power system for particle accelerator. Methodology has been demonstrated by developing two different compact ampliﬁers with power output of 2 kW each, operating at 352 MHz and 505.8 MHz, respectively. This paper describes underlying design principles and indigenous development of these ampliﬁers, consisting of 270–300 W ampliﬁer modules, 8-way 2 kW radial combiner/divider and directional couplers. Design methodology for power combiner has been extended by physically realizing higher power (4 kW) 16-way power combiner and 2-way combiner (8 kW) for higher power (8 kW) ampliﬁer conﬁguration planned. Simple design, indigenous technology, high efﬁciency and ease of fabrication, are the main features of this design.