Lakhindar Murmu

A Dual - Band Bandpass Filter for 2 . 4 GHz Bluetooth and 5 . 2 GHz WLAN Applications

In this paper a dual-band bandpass filter, using stub loaded ring resonator and etched nested C-shape defected ground structure (DGS), is reported. The operating frequencies of the bandpass filter conform to the Bluetooth (2.4 GHz-2.484 GHz) and WLAN (5.15 GHz-5.35 GHz) systems. Due to its applications in WLAN and Bluetooth systems, the filter will be subjected to high EM radiation from the antenna and nearby sources. Therefore, susceptibility study of such filter is very important. The susceptibility study of the filter has been carried out by subjecting the structure to an interference source. Experimental results are presented and analyzed.

A simple wideband microstrip bandstop filter for WLAN and WiMAX band rejection purpose

In this paper, a simple hexagonal wideband microstrip bandstop filter with an open-end stepped impedance stub has been proposed for the rejection of WLAN and WiMAX bands. Controlling the dimensions of the shunt open-end stepped impedance stub, the rejection bandwidth and the level of rejection can be controlled. The structure is very simple and is also easy to fabricate. The final filter structure provides a stop band that extends from 3.19 GHz to 5.36 GHz within and more than -20dB rejection and hence it can reject the 3.5 GHz WiMAX bands and 5.2 GHz WLAN frequency bands. The simulated response has been validated after comparing it with the measured data.

A compact branch-line coupler using folded microstrip lines

This paper presents a compact 3 dB Quadrature branch-line coupler using folded microstrip line geometry. Commercially available IE3D software has been used to design and simulate the structure. The proposed structure is simple and takes lesser optimization time. It has been shown that the structure provides about 43.63% compactness compared to the conventional branch line coupler. The structure, therefore, can be incorporated in the microwave circuit design where medium level compactness and faster design are preferred.

Waveguide bandpass filter with easily adjustable transmission zeros and 3-dB bandwidth

ABSTRACT This paper presents a compact waveguide bandpass filter with adjustable transmission zeros (TZs) and bandwidth. The design provides the flexibility to place the TZs at the desired locations for better interference rejection. To demonstrate, initially a three-pole bandpass filter has been designed by placing three single slot resonator structures inside a WR-90 waveguide. Next, two additional asymmetrical slot structures have been used with each of the above resonators to generate two TZs, one on each side of the passband. Since three resonators were used, this process results in six asymmetric slot structures those results in six TZs. The final filter operates at 9.98 GHz with a 3-dB bandwidth of 1.02 GHz and TZs at 8.23/8.70/9.16/10.9/11.6 and 13.115 GHz. Equivalent circuits and necessary design equations have been provided. To validate the simulation, the proposed filter has been fabricated and measured. The measured data show good agreement with simulated data.

A Dual-Band Bandpass Filter Using Quad-Mode Resonator for Bluetooth and WLAN Applications

This paper presents a quad-mode dual-band bandpass filter (BPF) using one shorted stub and two pairs of open stubs. The proposed filter simultaneously operates at Bluetooth (2.4–2.485GHz) and WLAN (5.1–5.35GHz) band. The filter has been designed and fabricated on Rogers’s RO4350 substrate and has a size of 13 × 12.26mm2.

A compact tri-band bandpass filter using multi-mode stub-loaded resonator

In this paper, a compact tri-band bandpass filter has been designed with three passbands which are located at 0.92, 2.08 and 3.59 GHz. The stub-loaded technique has been used to attain the triple passband bandpass filter and the open stubs have been coupled with each other to minimize the circuit size. The designed filter has tolerable passband insertion losses of 0.41, 1.39, and 1.97 dB respectively with the respective return losses of above 27.7, 12.3, and 16.2 dB.

A Compact Quad-Band Bandpass Filter Using Multi-Mode Stub-Loaded Resonator

This paper presents a compact shorted stub-loaded quad-band bandpass filter. The proposed filter simultaneously operates at GSM (0.83-0.97 GHz), LTE2300 (2300-2400 MHz), WiMAX (3.3-3.7 GHz), and WLAN (5.725-5.825 GHz) bands. The filter has been designed using the technique of stub-loaded resonator (SLR). By changing the length of the center-loaded stub, the resonant frequency of the even-mode can be varied without affecting that of the odd-mode. This simplifies the design and tuning of the quad-band filter. Eight transmission zeros (TZs) around the three passband make the pass bands highly isolated. In order to validate its practicability, a quad-band bandpass filter (BPF) has been designed, fabricated and measured. Good agreement between simulated and measured results is observed.

Wideband microstrip bandpass filter using stub-loaded resonator

In this article, a wideband bandpass filter (BPF) using half-wavelength resonator tapped in the middle with loaded stub is presented. The proposed filter has 3-dB fractional bandwidth (FBW) of 75% with a very sharp cutoff due to two transmission zeros at lower and upper stop-bands. It has low passband insertion-loss with good return-loss characteristics.

Hexagonal bandpass filter using open end step impedance stub perturbation

A novel dual-mode hexagonal loop resonator bandpass filter with a step impedance open-end stub perturbation is proposed along with possible applications. It is shown that different responses can be realized using only a single dual-mode resonator by changing the parameters of the perturbation. As compared to rectangle and square counterparts the interior angles are large in hexagonal geometry which promises better confinement in the microstrip circuits. The structure is very simple, easy to fabricate and useful for communication system.