Improved Interference Rejection of Mobile Base Station

TEM filters are widely used by cellular base stations due to their high Q, low cost and extremely broad spurious-free stopband [1]. There are increased demands for low loss filters that are compact and have excellent in-band and out of band characteristics. The dielectric resonator filters are also

Project Title

Improved Interference Rejection of Mobile Base Station

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

TEM filters are widely used by cellular base stations due to their high Q, low cost and extremely broad spurious-free stopband [1]. There are increased demands for low loss filters that are compact and have excellent in-band and out of band characteristics. The dielectric resonator filters are also ideal candidates for cellular base stations due to their high quality factor and miniaturized volume [2].

The first dielectric resonator filter was introduced by Cohn in 1968 having a relative permittivity of 100 and loss tangent of 0.0001. Ceramic materials are evaluated by their Q factor, permittivity, and temperature [3]. The major drawbacks of these filters are their crowded spurious modes near the passband. This proximity of higher order modes creates a significant challenge to design a filter which meets commercial base stations’ out of band rejection specifications [4]. This closes proximity of other spurious frequencies allows other mobile carriers to interfere the transmission of mobile base stations. In [5], the high permittivity dielectric waveguide filter achieved 50% size reduction in comparison with the air filled TEM filter, but the designed filter suffers from crowded higher order modes resonating near the passband.

In this project, a new design techniques to improve the spurious performance of ceramic loaded waveguide filters is presented. This improved performance will certainly help to improve the interference rejection of mobile base station, which results in good performance of any mobile base station. In ceramic loaded filter configuration we uses rectangular ceramic blocks of same widths with blind hole configuration, placed inside a metal cavity with the top and bottom surfaces touching the cavity walls. Spurious mode frequency separation increases by introducing blind holes in every ceramic blocks.

Experimental results of dielectric/ceramic loaded filter designs will be presented along with electromagnetic (EM) simulations.

Project Objectives

A new type of ceramic loaded filter for mobile base station will be realized in waveguide technology, which offers great improvement in stop band performance and reduces the interferences from other mobile carriers.

Project Implementation Method

• Literature review of different kind of mobile base stations filters and already existing solutions
• Circuit Simulations of band pass filters using any circuit simulator
• Electromagnetic  Simulation of waveguide resonator using HFSS
• Electromagnetic Simulation of Ceramic loaded waveguide filter using HFSS
• Purchase of Ceramics
• Realization and Fabrication of Ceramic Loaded Filter
• Thesis Writing
• Final Presentation

Benefits of the Project

We are working on a microwave base station filter, which is capable of eliminating the stopband interference for mobile base stations. Previously this kind of function can be performed by two filters (bass pass and low pass) but now this interference rejection filter allows us to put the characteristics of bandpass and lowpass filter in one filter which helps us to reduce the overall volume of Mast at base stations without affecting the performance of a base station filter. we will design this filter at 1845 MHz of frequency and expecting to achieve the stopband interference rejection up 5000 MHz. This design technique can also be implemented in some other frequencies of satellite communication which will surely help the organization like SUPARCO Pakistan. This will help the cellular companies as well as the SUPARCO Pakistan to achieve such kind of response with the use of only one filter which will greatly reduce the cost and size of the MAST and satellite which is of utmost importance.

Technical Details of Final Deliverable

we will design a new type of six order dielectric-loaded filter with ceramic blocks of permittivity of 43. The concept of a blind hole in each ceramic block will allow us to get the good spurious frequency and to achieve the miniaturized size for the filter. The same design will be fabricated in waveguide technology having the ceramic block at the center of each resonator. Bismillah Electronics at Lahore will help us to fabricate this filter while the high permittivity ceramic blocks will be imported from china Compony named "Gova Tech". In the last, the fabricated filter will be tested on a network analyzer that is available in Sukkur IBA and then tries to publish these results in some reputed international impact factor journal.

Final Deliverable of the Project

Hardware System

Core Industry

Telecommunication

Other Industries

Education

Core Technology

Others

Other Technologies

Sustainable Development Goals

Industry, Innovation and Infrastructure

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com