An antenna apparatus utilizing an aperture of transmission line, which is connected to a first transmission line having a predetermined characteristic impedance, includes a tapered line portion, and an aperture portion. A trading party may control the amount of future financial exposure that the trading party will incur with any counterparty in one or more future time periods in trades by the trading party during a trading session. The planar portion comprises a first edge and a second edge. Then, transmitting a child device number CID of the user’s own apparatus at the E slot designated by the parent device packet, the user’s own apparatus transmits a connection request to the parent device. The baffle plate is configured to divide the first fluid passageway into a first flow path and a second flow path, where the first array of fluid conduits extends through the first flow path and the second array of fluid conduits extends through the second flow path.