Apple’s shares climbed and rumors sizzled ahead of an expected move on Tuesday to expand the iPhone domain with a pair of new models, including one aimed at China.

Analysts believe a special event at Apple’s headquarters in Silicon Valley will spotlight a more economical iPhone priced to compete in emerging markets where money is tight, along with a beefed-up top-end model.

“The key challenge for Apple this week is to demonstrate that it can maintain momentum in overall iPhone sales, and to do so in a way which won’t drive down margins significantly,” said Ovum chief telecom analyst Jan Dawson.

“It’s key for Apple to be able to find ways to drive growth at a higher rate again, and getting China’s biggest carrier on board and launching a cheaper version of the iPhone are both key to doing that.”

Apple became a Wall Street darling by pairing blistering sales of culture-changing gadgets such as iPods, iPhones, and iPads with enviable “margins,” the difference between cost and price.

Forrester analyst Charles Golvin told AFP the consensus is for Apple to unveil a new high-end phone, “most likely called the 5S, with the same look and feel physically but with a speed boost; new processor, and new graphics capabilities.” (AFP)