Budhaditya Majumdar

A single band beam scanning active phased array antenna

A fixed frequency phased rectangular microstrip antenna array is proposed. It consists of two patch antennas places side by side and one element is fed with a meandered phase delay. Additionally varactor diodes have been used to vary the overall phase delay for beam scanning. The design avoids any additional bias paths and only on external bias-tee is required for biasing. A prototype that can scan its main lobe between 7° and 32° and with the resonance frequency tunable between 2027 MHz and 2210 MHz, under different bias conditions, has been fabricated as a proof of concept. The fabricated antenna also has an additional tunable resonance between 2356 MHz and 2450 MHz.

Additive manufacturing of a dual-ridged horn antenna

A 3D printed dual-ridged horn antenna (DRHA) is presented. The antenna design is optimized for additive manufacturing and is 3D printed using acrylonitrile butadiene styrene (ABS) and then painted with nickel based aerosol spray. The coaxial transition is also included in the 3D printed prototype. The antenna was manufactured with the intention of improving learning and education of electromagnetism and antennas for undergraduate students using a low-cost personal desktop 3D printer. The painted DRHA has a 10 dB return-loss bandwidth of 6621MHz (1905MHz–8526MHz) with a peak gain of 11 dBi. This prototype is the first known ABS-based horn antenna with the coaxial transition embedded into it.

Extended Transmission-Line Modelling of Inset-Fed Reconfigurable Rectangular Microstrip Antennas

An extended transmission-line model is presented for an inset-fed rectangular microstrip patch antenna. The transmission-line model agrees to the cos4 impedance variation for inset-fed microstrip antennas with an addition of a corrective extended feed length upto the inner radiating edge. Verification of the model’s complex reflection coefficient is concluded with good agreements with measured results. Further extension of the transmission-line model with for or more thin shorting post connected to multiple varactor diodes have been conducted. Fourty two test cases across five independent antenna designs have been worked upon. Results obtained using the transmission-line model are compared with those obtained with a 3D full-wave solver and measurements. In 69% of the test cases, the transmission-line models have less than 3% deviation to the measured or simulated results. 41% of them have less than 1% deviation. For the first two antennas, both simulated and measured results were compared with the transmission-line model. For the rest of three, results from the transmission-line model were compared to the simulated ones.

A simple reconfigurable patch antenna for mobile applications

A reconfigurable patch antenna is proposed. The antenna design was made with the ambition of not having any potentially interfering DC bias lines and would be operational only with an external bias-tee. The reconfigurable modes make the patch antenna resonant at two frequencies of 1810 MHz and 2035 MHz, for ON and OFF states of the PIN diode, respectively.