All perfect praise be to Allah The Lord of The Worlds. May His blessings and peace be upon our Prophet Mohammad and upon all his family and companions. 

Reciting Al-Faatihah is a pillar of prayer; therefore, the prayer of the one who doesn`t recite it is considered invalid. This ruling applies to the person leading the prayer(Imam), the persons led in prayer, and the person praying solely, whether that prayer was silent, non-silent, supererogatory or obligatory, as indicated by the following Hadith: "The prayer of the one who doesn’t recite Al-Faatihah is invalid" {Related by Bukhari and Muslim}. Al-Imam An-Nawawi said: "Reciting Al-Faatihah is an obligatory act of prayer, one of its pillars, must be recited itself, must be recited in Arabic, can`t be replaced by another verse, must be recited in all types of prayer: supererogatory, obligatory, silent, or non-silent, must be recited by the man, the woman, the traveler, the boy, the standing, the sitting, and the one praying while lying on his side, and this applies to the Imam, those praying behind him and the one praying solely." {Al-Majmou` vol.3/pp.326}. 

It was narrated from Abu Sa’ib that he heard Abu Hurairah say: “The Messenger of Allah (PBUH) said: "Whoever performs a prayer in which he does not recite Ummul Qur’an (the Mother of the Qur’an, i.e., Al- Fatihah), it is deficient; not complete.” I said: ‘O Abu Hurairah, sometimes I am behind the Imam. He pressed my forearm and said: ‘O Persian! Recite it to yourself." {Related by Muslim}. 

The above indicates that whoever is led in prayer is obliged to recite Al-Faatihah, but if he doesn`t, then he isn`t free from the liability, except if he joined the prayer late, and the Imam was bowing (Ruku`). In this case, the Imam`s recitation of Al-Faatihah avails him.

 In principle, the Imam should pause(keep quiet) after reciting Al-Faatihah in order for those behind him to recite it, as the Prophet(PBUH) used to do. It was narrated that Samurah bin Jundab said: “There are two pauses which I memorized from the Messenger of Allah (PBUH), but `Imran bin Husain denied that. We wrote to Ubayy bin Ka`b in Al-Madinah, and he wrote that Samurah had indeed memorized them.” (One of the narrators) Sa`eed said: "We said to Qatadah: 'What are these two pauses?' He said: When he started his prayer, and when he finished reciting." Then later he said: "And when he recited: 'Not (the way) of those who earned your anger, nor of those who went astray.' They used to like (for the Imam) when he had finished reciting to remain silent until he had caught his breath." {Abu-Dawood}. However, if the Imam didn`t pause after he recited Al-Faatihah, those praying behind him remain liable for it, so they may recite it fast, although the Imam is reciting. And Allah The Almighty Knows Best.