Jugul Kishor

Formulation of size reduction technique in microstrip circuits by using DGS and DMS

In this work a simplified and accurate mathematical formula is derived to predict the reduced dimension of the microstrip circuit by using applicable etching geometry on plane of microstrip circuit such as DGS/DMS that will affect the resonance frequency of microstrip circuit in desired direction due to increment of slow wave effect. Here we developed proportional formula of defect which is verified successfully by applying to network implemented with an open circuit and for microstrip patch antennas, phase shifter.

Designing of Varactor tuned microstrip patch antenna

A varactor tuned microstrip patch antenna has been designed and developed, with a view to predicting the obtainable tunable range. Tunability is achieved by connecting varactor diodes thus altering the capacitance of the patch and hence resonant frequency. Although this antenna has a narrow instantaneous bandwidth, electronic tuning allow a large band to covered whilst maintaining the same good narrow band operational characteristics. Evaluation of the antennapsilas performance is provided by practical results.

A novel compact hexagonal double dumbbell shaped LPF with high steepness and wide rejection bandwidth

In this paper a novel compact wideband high rejection low-pass filter is presented. The low pass filter (LPF) consists of two hexagonal dumbbell shaped resonator placed perpendicular to each other. With such structure undesired harmonics are effectively suppressed with improvement in the stop band and sharpness factor. The proposed filter also has constant group delay within the rejection band. The new filter has compact configuration even better filter properties than the traditional filter. This design gives insight in designing a low-pass filter with reduced size of an arbitrarily shape. Using electromagnetic simulation software, it is shown that a compact LPF with 4.7GHz cutoff frequency and band reject of up to 16GHz has been successfully designed and simulated.

Designing of a compact microstrip antenna resonating at 4.8GHz by using size reduction technique

In this work a compact microstrip antenna has been design and developed. This antenna incorporated two symmetrical DMS like etching structure along length on patch surface of the antenna to minimize the size. Unlike normal antenna DGS/DMS introduces discontinuities on the signal plane which in turn disturbs shielded current distribution in signal plane. Due to which apparent permittivity of the substrate varies as a function of frequency and play important role in the performance of the antenna. A size reduction of 40% at 4.8GHz was observed. We also calculate all other parameters like apparent permittivity, phase velocity of wave, equivalent inductance and capacitance. Here we implement proportional formula of defect in three steps to get compact size of antenna which has higher impedance bandwidth w.r.t conventional patch antenna approximately 23.1MHz. For this work we care the overall performance like radiation pattern, efficiency, gain, directivity, polarization should not degraded by inserting slot. Here we also observe that performance of antenna is a function of shape, size, and position of DMS which is inserted. We use symmetrical DMS along length to avoid cross polarization. We not prefer here to use DGS because DGS also acts as radiating element which increases the back lobe radiation.