Shares in Filtronic plunged 56% on Wednesday after forecast sales Massive MIMO antennas are set to be much lower than previously thought.

Sales in the six months to the end of October at the Antennas and telecoms filters maker were down from £12.8 million last year to £10.4 million.

The group expects to make a loss for the current financial year.

The group said in a statement: “Our predominant OEM customer, with whom we had closely collaborated in the development of this product range, has now significantly lowered its forecast demand below that which it had previously provided, having itself been advised that its lead client is now looking to deploy different frequencies to those it had originally indicated.”

“As a consequence of this lower demand and the uncertainty it brings, the Board has decided to impair fully the net book value of the capitalised development costs of £0.5 million relating to the development of mMIMO in its half year results.”

“The Company has made considerable efforts to diversify its customer base in recent years and despite this obvious set back to our mMIMO antennas business, we are pleased to advise that we were recently approved as a supplier of a niche antenna product to a Tier 1 Mobile Network Operator in South Africa. However, given the importance of mMIMO to our future plans in the antenna business, the Board has commenced a review of its options for this component of the Group.”

Shares in Filtronic (LON: FTC) are trading down 56.06% at 7,91p (1127GMT).