Prior to being appointed by Oxford, Buckingham coached in New Zealand, Australia and India, where he was in charge of Mumbai City.
He replaced Liam Manning at the Kassam Stadium with the team second in the table, and although they fell short of automatic promotion, a return to the Championship was secured with a 2-0 win over Bolton at Wembley.
Three wins and three losses at the start of the current league campaign were followed by five consecutive draws, but since then they have only taken four points from the past eight matches.
Speaking following Saturday’s defeat, he told BBC Radio Oxford: “I am who I am and we will always be as honest as we can with the media, fans or the players and they know that. We’ve shown the success of that together.
“We will find ways to make sure we continue to challenge ourselves at this level and also make sure we put things in place to get back to getting the results we all want.
“Our aim this year was to stay in this league, that is the reality of it.”
Asked if he had a message for fans, he added: “The key thing for me is they’ve stuck with us through thick and thin, it’s been a rollercoaster since I arrived.
“There’s been lots of highs, we haven’t had many lows – at the moment, people will look it as a low, but these are the moments we are tested as a playing group and tested as a club.”