Normally without a SIM card, this is difficult. However, there are times a phone is stolen and a person will immediately remove the SIMs card. There are location finders that you can use to try and track your phone. They will use a radio signal to track your device. Normally all cell phone has a GSM protocol that will allow anyone to use this phone to make emergency calls with the device. Therefore, the phone is transmitting a signal from the device and it can be tracked by this signal.
If the phone doesn't have a SIMs card and has been used for an emergency call the IMEL can be traced back to this device. Therefore, if you can tap into this signal it is possible to track your phone. I knew a person who thought they could get away with some illegal activity on their phone by removing the SIMs card. This didn't work and the police were able to track the device and it leads them right to this person.