reader design for RFID

hi
i want to design an rfid reader for frequency 125khz or 13.56Mhz. But range is about 3 to 4 feet. I know the range of these readers are less but my question is can we improve the range of 13.56Mhz reader to 4 feet by increasing the antenna size as large as possible. i am not bother about the size of the reader.can i design..?

thank you