'imminent advent' is correct and usable in written English.
You can use it to refer to something that is about to happen. For example: The imminent advent of winter brought an icy chill to the air.
As the electronics industry is heavily focused on battery charge length – in everything from tablets to the new generation of wearable tech such as the imminent iWatch – the advent of any new form of battery attracts major interest.
They refrained from setting a new date for that visible appearance, but they insisted that Christ's advent was imminent.
For example, why do local leaders think that the advent of a post-American Af-Pak region free of U.S. influence is imminent?
He was sent to Alexandria under house arrest in 1309, the day after the abdication of the sultan Muḥammad ibn Qalāwūn and the advent of Baybars II al-Jāshnikīr, whom he regarded as a usurper and whose imminent end he predicted.
Advent International bought Charlotte Russe.
Evercore advised Advent and Goldman Sachs.
