Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
We used to get a bow-tie antenna with tv's. For receiving broadcasts on uhf channels.
About nine inches across. Two leads coming out. Rough shape was a loop but the wires were bent to be close together in the center. At the center was a plastic notch which would attach to the rabbit ears (the larger antenna for vhf channels).
I don't know that the bow-tie is necessarily a better shape for an antenna than the loop. The bowtie could ride on the rabbit ears, thus it was easy to move it around and raise it higher for better reception. The loop antenna on the other hand generally stayed in a fixed position.
A bow-tie antenna is in principle a "thick" dipole; at VHF and UHF, you can use equally well (electrically) two triangles cut of metal sheet.
The advantage of this structure is that it is a good dipole for a wider frequency band. In some cases it was found later that cutting the triangles into a pair of narrower "fingers" and setting the dipole length to one wavelength was better for wideband matching to e.g. 300 Ohms.