Please check the website of Apex body of universities in Bangladesh, and compare the universities strengths and select best one for doing Ph.D. However, I belong to India.
Indian Institute of Science is the only Indian institution ranked in Shanghai list of top Universities. They have management studies. Good luck in your career dear @Mizanur!
There are so many good/ reputed Institutes/ Universities in India, where any scholar (like you) from Business Management can do PhD (or Fellow Program, called FPM). FPM is equivalent to PhD degree, offered by leading IIMs. IIMs, as can be verified easily, have got international reputation. You can check site of the regulating bodies (for higher education in India) like, UGC and AICTE for details, and then respective institute's websites. One has to go through formal (rigorous) selection process, before getting admitted/ selected (particularly in those PhD/ FPM programs, where one gets fellowships/ financial assistance.).
I don't agree with Ljubomir's information that IISc is the only (reputed) institute (particularly when, one is searching Management PhD programs).
We should refer appropriate ranking/ indexing information, may be country specifics and program/ subject specific.