Ka-band (32-GHz) radio communication links are more adversely affected by atmospheric noise temperature than X-band (8.4-GHz) or S-band (2.9-GHz) links. As a result, the strategy for telecommunications between a spacecraft employing Ka-band and the Deep Space Network is necessarily different from that employed at the lower frequencies. To aid in the development of new communication strategies, ...

A family of sets {A k } is called a strong d system if the intersection of any two of its members is the same, i .e ., if A kI n a = A ka n A ka . It is called a weak d system if I A k= rn A k . 1 is the same for any two sets of our family . J systems have recently been studied in several papers . f (n, r) is the smallest integer for which any family of f (n, r) sets A k , I < k < f (n, r) of s...

In the Bengal Basin, the land surface exposed during the last lowstand of sea-level around 20 ka, and now buried by Holocene sediment, is capped by an impermeable clay palaeosol that we term the Last Glacial Maximum Palaeosol (LGMP). The palaeosol strongly affects groundwater flow and controls the location of arsenic pollution in the shallow aquifers of our study site in southern West Bengal an...

Dating back as far as 100 ka, the Blombos ochre and the Diepkloof ostrich egg engravings are considered among the earliest fossilized evidence of human symbolic behavior. Of special interest to this study is the temporal trajectory spanning more than 30 thousand years from earlier simpler parallel line patterns to later complex cross-hatchings suggesting adaptive compositional development. Thro...

The rectangular dielectric waveguide (RDWG) technique has been developed for the determination of the dielectric constant of materials from effective refractive index measurements in the Q and W bands. This paper describes the use of an optimization method in conjunction with the RDWG technique for the determination of both the dielectric constant and loss tangent of materials at Ka-Band. The e...

This article summarizes the design concepts applied in the development of an advanced Ka-band (34.4 GHz/32 GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2 GHz/8.4 GHz) deep-space transponder (DST) to provide Ka-band up/Kaand X-band down capability. In addition, it can also be configured to provi...

1 Correction to the Airy Approximation In Ref..1] and especially in Franz and Galle 2] one can nd correction terms to order O((ka) ?5=3) to the standard Airy approximation of the zeros l of the Hankel function H (1) (ka) in the complex-plane 1 : l = ka + e ii=3 (ka)

Let k be a positive integer and let A ⊂ Z. We let k · A = {ka : a ∈ A} denote the k-dilation of A, and let kA = A+ · · ·+ A (k-times) be the k-fold sumset of A. We observe that A+ k · A ⊂ A+ kA = (k + 1)A and that, in general, A+ k · A is much smaller than (k + 1)A. It is well known that |(k + 1)A| (k + 1)|A| − k, and that equality holds only if A is an arithmetic progression. Indeed, if A is a...

India is planning to conduct its own Ka band propagation studies experiment in order to validate the existing ITU model and to develop a more accurate prediction model for its unique climate condition for guaranteed QoS. This experiment involves measurement of signal attenuation due to rain and development of appropriate mathematical propagation models. This requires a ground receiver to receiv...