Even more so than 70cm, you can achieve very high gain with a small antenna. Although you do need to be very accurate with your measuring and cutting. Another side-effect is that higher antenna gains mean narrower lobes. So you need to be more accurate with your pointing. Or, particularly if your activity involves working though local repeaters over a fairly unobstructed path, you may be able to get away with omnidirectional low gain vertical antennas.
Here's some practical ideas to get you thinking on 23cm antennas:
* DJ9YW 23cm yagi for DX
* PA4DAN 23cm yagi
* VK1AD's 12 element yagi for portable work
* VK1AD's compact bi-quad antenna
* WA6SVT omnidirectional vertical collinear
PS: After portable antennas for lower frequencies? There's ideas in the top-selling Hand-carried QRP antennas. Available in ebook or paperback it's been favourably reviewed by hams all around the world.