Design and optimization of a parallel-coupled microstrip bandpass filter for Software Defined Telescope is presented in this paper. The simulation and optimization is done using ADS and Momentum. The filter is designed and optimized at a center frequency of 1.42GHz. The filter is built on a relatively cheap substrate FR-4 with permittivity 4.4 r   and loss tangent tan 0.02  . Simulation results reveal that the filter operation is optimum over the frequency range 1.41 GHz to 1.44 GHz. The 3 dB bandwidth is thus 300 MHz. the return loss is below-10 dB over the passband. Insertion loss is-2.806 dB in the passband. The filter is almost matched to the characteristic impedance (0 Z), 50 Ohms. Also it is observed that the phase varies linearly with frequency. The filter once fabricated could be used at the radio receiver of the Software Radio Telescope to filter out terrestrial radio interference.

In this paper, a novel OLR loaded self complementary dipole antenna (OSCDA) is proposed. Open loop resonators (OLRs) are introduced into the design of a traditional self complementary dipole antenna (SCDA), to evolve it into OSCDA. The antenna is compact and has an impedance bandwidth of 1.1 GHz to 3.3 GHz with VSWR less than 2 across the frequency band. The use of the proposed antenna as a liquid sensor to detect adulteration in liquids is demonstrated from the relationship between concentration and shift in resonant frequency and variation in reflection coefficient. Variation of reflection coefficient due to change in dielectric properties is studied for different cases viz.: (i) dilution of milk with water, (ii) adulteration of coconut oil with rice bran oil, (iii) adulteration of honey with sugar syrup, and (iv) varying concentration of salt and sugar in water. When an adulterant is added to a liquid or concentration of solute in a solution varied, the dielectric properties change. This is reflected in the variation in reflection coefficient and resonant frequency. Experimental results show that the antenna has a good sensitivity to detect adulterated samples.

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In this paper, a printed split ring resonator (SRR) loaded log-periodic Koch dipole antenna (SLPKDA) is proposed. Koch-shaped dipoles when being loaded with split ring resonator (SRR) yielded a compact antenna, still preserving the radiation properties of log-periodic dipole antenna (LPDA). Measurement results show that the proposed antenna has a wide bandwidth, good impedance match and gain of 4 dBi over the band of frequencies from 0.9 GHz to 2.5 GHz. Both vertical and horizontal dimension reductions are achieved by loading Koch dipoles with SRR.

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