NISCAIR Online Periodicals Repository Collection: IJRSP Vol.35(5) [October 2006]

Design of wideband and multiband microstrip array antennas

Thu, 28 Sep 2006 22:58:59 GMT

Title: Design of wideband and multiband microstrip array antennas

Authors: Konda, R B; Pushpanjali, G M; Mulgi, S N; Satnoor, S K; Hadalgi, P M; Hunagund, P V

Abstract: A method for improving the impedance bandwidth of microstrip array antenna by incorporating a slot in the radiating patches is presented. It is further described by using a common parasitic element, which is gap-coupled to the radiating edges of the rectangular patches and embedding a slot in the parasitic element. The use of gap-coupling and slot in the parasitic element makes the antenna to have wider impedance bandwidth and leads to its operation at more than one band of frequencies. The design concepts of antenna are described and experimental results discussed. These antennas may find application in mobile communication.

Page(s): 372-375

Occurrence of type-I radio bursts and their association with solar cycle

Thu, 28 Sep 2006 22:58:59 GMT

Title: Occurrence of type-I radio bursts and their association with solar cycle

Authors: Gupta, Meera; Mishra, V K; Tiwari, D P; Mishra, A P

Abstract: A minimum between solar cycle 22 and 23 has been defined earlier on the basis of type-I radio burst only. In the present paper a re-visit to the occurrence of type-I radio bursts in relation to general level of solar activity (sunspot number) is made covering the minima of cycle 21 to complete cycles 22-23. The study shows that, it is not appropriate to speculate solar cycle minima on the basis of type-I radio burst only.

Page(s): 324-326

A new velocity dependent variable hysteresis-margin-based call handover scheme

Thu, 28 Sep 2006 22:58:59 GMT

Title: A new velocity dependent variable hysteresis-margin-based call handover scheme

Authors: Bhattacharya, P P; Banerjee, P K

Abstract: The increase of mobile users compels the uses of picocells in cellular mobile communication and the task of handover becomes critical. Handover response should be faster and also should depend on mobile velocity to avoid unwanted call termination for high velocity mobiles and unnecessary handover for low velocity mobiles. In this paper, a path loss exponent and user-velocity-dependent variable hysteresis-margin-based call handover algorithm is proposed and studied. The handover algorithm is tested and found to give desired response.

Page(s): 368-371

IMF and geomagnetic activity during the solar wind disappearance event

Thu, 28 Sep 2006 22:58:59 GMT

Title: IMF and geomagnetic activity during the solar wind disappearance event

Authors: Vats, Hari Om

Abstract: There was a very peculiar situation reported during 11-12 May 1999, that the "solar wind disappeared". This was one of the long lasting, low velocity and low density solar wind events and was caused by the passage of a “void” around the earth and its environment. The interplanetary magnetic field (IMF), especially, the north-south component (B_z) remained quiet during the event. However, it showed a fast and intense fluctuation after the passage of this low solar wind region or “void”. The equatorial D_st and A_p variations indicate a mild geomagnetic storm after the passage of void. This mild geomagnetic storm is probably due to fluctuations in B_z whose value varies from –12 to 9 nT.

Page(s): 307-311